Update vendor (#1265)

17 files changed, 1450 insertions, 0 deletions

diff --git a/vendor/github.com/hashicorp/errwrap/LICENSE b/vendor/github.com/hashicorp/errwrap/LICENSE
new file mode 100644
index 00000000..c33dcc7c
--- /dev/null
+++ b/vendor/github.com/hashicorp/errwrap/LICENSE
@@ -0,0 +1,354 @@
+Mozilla Public License, version 2.0
+
+1. Definitions
+
+1.1. “Contributor”
+
+     means each individual or legal entity that creates, contributes to the
+     creation of, or owns Covered Software.
+
+1.2. “Contributor Version”
+
+     means the combination of the Contributions of others (if any) used by a
+     Contributor and that particular Contributor’s Contribution.
+
+1.3. “Contribution”
+
+     means Covered Software of a particular Contributor.
+
+1.4. “Covered Software”
+
+     means Source Code Form to which the initial Contributor has attached the
+     notice in Exhibit A, the Executable Form of such Source Code Form, and
+     Modifications of such Source Code Form, in each case including portions
+     thereof.
+
+1.5. “Incompatible With Secondary Licenses”
+     means
+
+     a. that the initial Contributor has attached the notice described in
+        Exhibit B to the Covered Software; or
+
+     b. that the Covered Software was made available under the terms of version
+        1.1 or earlier of the License, but not also under the terms of a
+        Secondary License.
+
+1.6. “Executable Form”
+
+     means any form of the work other than Source Code Form.
+
+1.7. “Larger Work”
+
+     means a work that combines Covered Software with other material, in a separate
+     file or files, that is not Covered Software.
+
+1.8. “License”
+
+     means this document.
+
+1.9. “Licensable”
+
+     means having the right to grant, to the maximum extent possible, whether at the
+     time of the initial grant or subsequently, any and all of the rights conveyed by
+     this License.
+
+1.10. “Modifications”
+
+     means any of the following:
+
+     a. any file in Source Code Form that results from an addition to, deletion
+        from, or modification of the contents of Covered Software; or
+
+     b. any new file in Source Code Form that contains any Covered Software.
+
+1.11. “Patent Claims” of a Contributor
+
+      means any patent claim(s), including without limitation, method, process,
+      and apparatus claims, in any patent Licensable by such Contributor that
+      would be infringed, but for the grant of the License, by the making,
+      using, selling, offering for sale, having made, import, or transfer of
+      either its Contributions or its Contributor Version.
+
+1.12. “Secondary License”
+
+      means either the GNU General Public License, Version 2.0, the GNU Lesser
+      General Public License, Version 2.1, the GNU Affero General Public
+      License, Version 3.0, or any later versions of those licenses.
+
+1.13. “Source Code Form”
+
+      means the form of the work preferred for making modifications.
+
+1.14. “You” (or “Your”)
+
+      means an individual or a legal entity exercising rights under this
+      License. For legal entities, “You” includes any entity that controls, is
+      controlled by, or is under common control with You. For purposes of this
+      definition, “control” means (a) the power, direct or indirect, to cause
+      the direction or management of such entity, whether by contract or
+      otherwise, or (b) ownership of more than fifty percent (50%) of the
+      outstanding shares or beneficial ownership of such entity.
+
+
+2. License Grants and Conditions
+
+2.1. Grants
+
+     Each Contributor hereby grants You a world-wide, royalty-free,
+     non-exclusive license:
+
+     a. under intellectual property rights (other than patent or trademark)
+        Licensable by such Contributor to use, reproduce, make available,
+        modify, display, perform, distribute, and otherwise exploit its
+        Contributions, either on an unmodified basis, with Modifications, or as
+        part of a Larger Work; and
+
+     b. under Patent Claims of such Contributor to make, use, sell, offer for
+        sale, have made, import, and otherwise transfer either its Contributions
+        or its Contributor Version.
+
+2.2. Effective Date
+
+     The licenses granted in Section 2.1 with respect to any Contribution become
+     effective for each Contribution on the date the Contributor first distributes
+     such Contribution.
+
+2.3. Limitations on Grant Scope
+
+     The licenses granted in this Section 2 are the only rights granted under this
+     License. No additional rights or licenses will be implied from the distribution
+     or licensing of Covered Software under this License. Notwithstanding Section
+     2.1(b) above, no patent license is granted by a Contributor:
+
+     a. for any code that a Contributor has removed from Covered Software; or
+
+     b. for infringements caused by: (i) Your and any other third party’s
+        modifications of Covered Software, or (ii) the combination of its
+        Contributions with other software (except as part of its Contributor
+        Version); or
+
+     c. under Patent Claims infringed by Covered Software in the absence of its
+        Contributions.
+
+     This License does not grant any rights in the trademarks, service marks, or
+     logos of any Contributor (except as may be necessary to comply with the
+     notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+     No Contributor makes additional grants as a result of Your choice to
+     distribute the Covered Software under a subsequent version of this License
+     (see Section 10.2) or under the terms of a Secondary License (if permitted
+     under the terms of Section 3.3).
+
+2.5. Representation
+
+     Each Contributor represents that the Contributor believes its Contributions
+     are its original creation(s) or it has sufficient rights to grant the
+     rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+     This License is not intended to limit any rights You have under applicable
+     copyright doctrines of fair use, fair dealing, or other equivalents.
+
+2.7. Conditions
+
+     Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+     Section 2.1.
+
+
+3. Responsibilities
+
+3.1. Distribution of Source Form
+
+     All distribution of Covered Software in Source Code Form, including any
+     Modifications that You create or to which You contribute, must be under the
+     terms of this License. You must inform recipients that the Source Code Form
+     of the Covered Software is governed by the terms of this License, and how
+     they can obtain a copy of this License. You may not attempt to alter or
+     restrict the recipients’ rights in the Source Code Form.
+
+3.2. Distribution of Executable Form
+
+     If You distribute Covered Software in Executable Form then:
+
+     a. such Covered Software must also be made available in Source Code Form,
+        as described in Section 3.1, and You must inform recipients of the
+        Executable Form how they can obtain a copy of such Source Code Form by
+        reasonable means in a timely manner, at a charge no more than the cost
+        of distribution to the recipient; and
+
+     b. You may distribute such Executable Form under the terms of this License,
+        or sublicense it under different terms, provided that the license for
+        the Executable Form does not attempt to limit or alter the recipients’
+        rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+     You may create and distribute a Larger Work under terms of Your choice,
+     provided that You also comply with the requirements of this License for the
+     Covered Software. If the Larger Work is a combination of Covered Software
+     with a work governed by one or more Secondary Licenses, and the Covered
+     Software is not Incompatible With Secondary Licenses, this License permits
+     You to additionally distribute such Covered Software under the terms of
+     such Secondary License(s), so that the recipient of the Larger Work may, at
+     their option, further distribute the Covered Software under the terms of
+     either this License or such Secondary License(s).
+
+3.4. Notices
+
+     You may not remove or alter the substance of any license notices (including
+     copyright notices, patent notices, disclaimers of warranty, or limitations
+     of liability) contained within the Source Code Form of the Covered
+     Software, except that You may alter any license notices to the extent
+     required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+     You may choose to offer, and to charge a fee for, warranty, support,
+     indemnity or liability obligations to one or more recipients of Covered
+     Software. However, You may do so only on Your own behalf, and not on behalf
+     of any Contributor. You must make it absolutely clear that any such
+     warranty, support, indemnity, or liability obligation is offered by You
+     alone, and You hereby agree to indemnify every Contributor for any
+     liability incurred by such Contributor as a result of warranty, support,
+     indemnity or liability terms You offer. You may include additional
+     disclaimers of warranty and limitations of liability specific to any
+     jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+
+   If it is impossible for You to comply with any of the terms of this License
+   with respect to some or all of the Covered Software due to statute, judicial
+   order, or regulation then You must: (a) comply with the terms of this License
+   to the maximum extent possible; and (b) describe the limitations and the code
+   they affect. Such description must be placed in a text file included with all
+   distributions of the Covered Software under this License. Except to the
+   extent prohibited by statute or regulation, such description must be
+   sufficiently detailed for a recipient of ordinary skill to be able to
+   understand it.
+
+5. Termination
+
+5.1. The rights granted under this License will terminate automatically if You
+     fail to comply with any of its terms. However, if You become compliant,
+     then the rights granted under this License from a particular Contributor
+     are reinstated (a) provisionally, unless and until such Contributor
+     explicitly and finally terminates Your grants, and (b) on an ongoing basis,
+     if such Contributor fails to notify You of the non-compliance by some
+     reasonable means prior to 60 days after You have come back into compliance.
+     Moreover, Your grants from a particular Contributor are reinstated on an
+     ongoing basis if such Contributor notifies You of the non-compliance by
+     some reasonable means, this is the first time You have received notice of
+     non-compliance with this License from such Contributor, and You become
+     compliant prior to 30 days after Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+     infringement claim (excluding declaratory judgment actions, counter-claims,
+     and cross-claims) alleging that a Contributor Version directly or
+     indirectly infringes any patent, then the rights granted to You by any and
+     all Contributors for the Covered Software under Section 2.1 of this License
+     shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
+     license agreements (excluding distributors and resellers) which have been
+     validly granted by You or Your distributors under this License prior to
+     termination shall survive termination.
+
+6. Disclaimer of Warranty
+
+   Covered Software is provided under this License on an “as is” basis, without
+   warranty of any kind, either expressed, implied, or statutory, including,
+   without limitation, warranties that the Covered Software is free of defects,
+   merchantable, fit for a particular purpose or non-infringing. The entire
+   risk as to the quality and performance of the Covered Software is with You.
+   Should any Covered Software prove defective in any respect, You (not any
+   Contributor) assume the cost of any necessary servicing, repair, or
+   correction. This disclaimer of warranty constitutes an essential part of this
+   License. No use of  any Covered Software is authorized under this License
+   except under this disclaimer.
+
+7. Limitation of Liability
+
+   Under no circumstances and under no legal theory, whether tort (including
+   negligence), contract, or otherwise, shall any Contributor, or anyone who
+   distributes Covered Software as permitted above, be liable to You for any
+   direct, indirect, special, incidental, or consequential damages of any
+   character including, without limitation, damages for lost profits, loss of
+   goodwill, work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses, even if such party shall have been
+   informed of the possibility of such damages. This limitation of liability
+   shall not apply to liability for death or personal injury resulting from such
+   party’s negligence to the extent applicable law prohibits such limitation.
+   Some jurisdictions do not allow the exclusion or limitation of incidental or
+   consequential damages, so this exclusion and limitation may not apply to You.
+
+8. Litigation
+
+   Any litigation relating to this License may be brought only in the courts of
+   a jurisdiction where the defendant maintains its principal place of business
+   and such litigation shall be governed by laws of that jurisdiction, without
+   reference to its conflict-of-law provisions. Nothing in this Section shall
+   prevent a party’s ability to bring cross-claims or counter-claims.
+
+9. Miscellaneous
+
+   This License represents the complete agreement concerning the subject matter
+   hereof. If any provision of this License is held to be unenforceable, such
+   provision shall be reformed only to the extent necessary to make it
+   enforceable. Any law or regulation which provides that the language of a
+   contract shall be construed against the drafter shall not be used to construe
+   this License against a Contributor.
+
+
+10. Versions of the License
+
+10.1. New Versions
+
+      Mozilla Foundation is the license steward. Except as provided in Section
+      10.3, no one other than the license steward has the right to modify or
+      publish new versions of this License. Each version will be given a
+      distinguishing version number.
+
+10.2. Effect of New Versions
+
+      You may distribute the Covered Software under the terms of the version of
+      the License under which You originally received the Covered Software, or
+      under the terms of any subsequent version published by the license
+      steward.
+
+10.3. Modified Versions
+
+      If you create software not governed by this License, and you want to
+      create a new license for such software, you may create and use a modified
+      version of this License if you rename the license and remove any
+      references to the name of the license steward (except to note that such
+      modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary Licenses
+      If You choose to distribute Source Code Form that is Incompatible With
+      Secondary Licenses under the terms of this version of the License, the
+      notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+
+      This Source Code Form is subject to the
+      terms of the Mozilla Public License, v.
+      2.0. If a copy of the MPL was not
+      distributed with this file, You can
+      obtain one at
+      http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular file, then
+You may include the notice in a location (such as a LICENSE file in a relevant
+directory) where a recipient would be likely to look for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - “Incompatible With Secondary Licenses” Notice
+
+      This Source Code Form is “Incompatible
+      With Secondary Licenses”, as defined by
+      the Mozilla Public License, v. 2.0.
+
diff --git a/vendor/github.com/hashicorp/errwrap/README.md b/vendor/github.com/hashicorp/errwrap/README.md
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index 00000000..444df08f
--- /dev/null
+++ b/vendor/github.com/hashicorp/errwrap/README.md
@@ -0,0 +1,89 @@
+# errwrap
+
+`errwrap` is a package for Go that formalizes the pattern of wrapping errors
+and checking if an error contains another error.
+
+There is a common pattern in Go of taking a returned `error` value and
+then wrapping it (such as with `fmt.Errorf`) before returning it. The problem
+with this pattern is that you completely lose the original `error` structure.
+
+Arguably the _correct_ approach is that you should make a custom structure
+implementing the `error` interface, and have the original error as a field
+on that structure, such [as this example](http://golang.org/pkg/os/#PathError).
+This is a good approach, but you have to know the entire chain of possible
+rewrapping that happens, when you might just care about one.
+
+`errwrap` formalizes this pattern (it doesn't matter what approach you use
+above) by giving a single interface for wrapping errors, checking if a specific
+error is wrapped, and extracting that error.
+
+## Installation and Docs
+
+Install using `go get github.com/hashicorp/errwrap`.
+
+Full documentation is available at
+http://godoc.org/github.com/hashicorp/errwrap
+
+## Usage
+
+#### Basic Usage
+
+Below is a very basic example of its usage:
+
+```go
+// A function that always returns an error, but wraps it, like a real
+// function might.
+func tryOpen() error {
+	_, err := os.Open("/i/dont/exist")
+	if err != nil {
+		return errwrap.Wrapf("Doesn't exist: {{err}}", err)
+	}
+
+	return nil
+}
+
+func main() {
+	err := tryOpen()
+
+	// We can use the Contains helpers to check if an error contains
+	// another error. It is safe to do this with a nil error, or with
+	// an error that doesn't even use the errwrap package.
+	if errwrap.Contains(err, "does not exist") {
+		// Do something
+	}
+	if errwrap.ContainsType(err, new(os.PathError)) {
+		// Do something
+	}
+
+	// Or we can use the associated `Get` functions to just extract
+	// a specific error. This would return nil if that specific error doesn't
+	// exist.
+	perr := errwrap.GetType(err, new(os.PathError))
+}
+```
+
+#### Custom Types
+
+If you're already making custom types that properly wrap errors, then
+you can get all the functionality of `errwraps.Contains` and such by
+implementing the `Wrapper` interface with just one function. Example:
+
+```go
+type AppError {
+  Code ErrorCode
+  Err  error
+}
+
+func (e *AppError) WrappedErrors() []error {
+  return []error{e.Err}
+}
+```
+
+Now this works:
+
+```go
+err := &AppError{Err: fmt.Errorf("an error")}
+if errwrap.ContainsType(err, fmt.Errorf("")) {
+	// This will work!
+}
+```
diff --git a/vendor/github.com/hashicorp/errwrap/errwrap.go b/vendor/github.com/hashicorp/errwrap/errwrap.go
new file mode 100644
index 00000000..a733bef1
--- /dev/null
+++ b/vendor/github.com/hashicorp/errwrap/errwrap.go
@@ -0,0 +1,169 @@
+// Package errwrap implements methods to formalize error wrapping in Go.
+//
+// All of the top-level functions that take an `error` are built to be able
+// to take any error, not just wrapped errors. This allows you to use errwrap
+// without having to type-check and type-cast everywhere.
+package errwrap
+
+import (
+	"errors"
+	"reflect"
+	"strings"
+)
+
+// WalkFunc is the callback called for Walk.
+type WalkFunc func(error)
+
+// Wrapper is an interface that can be implemented by custom types to
+// have all the Contains, Get, etc. functions in errwrap work.
+//
+// When Walk reaches a Wrapper, it will call the callback for every
+// wrapped error in addition to the wrapper itself. Since all the top-level
+// functions in errwrap use Walk, this means that all those functions work
+// with your custom type.
+type Wrapper interface {
+	WrappedErrors() []error
+}
+
+// Wrap defines that outer wraps inner, returning an error type that
+// can be cleanly used with the other methods in this package, such as
+// Contains, GetAll, etc.
+//
+// This function won't modify the error message at all (the outer message
+// will be used).
+func Wrap(outer, inner error) error {
+	return &wrappedError{
+		Outer: outer,
+		Inner: inner,
+	}
+}
+
+// Wrapf wraps an error with a formatting message. This is similar to using
+// `fmt.Errorf` to wrap an error. If you're using `fmt.Errorf` to wrap
+// errors, you should replace it with this.
+//
+// format is the format of the error message. The string '{{err}}' will
+// be replaced with the original error message.
+func Wrapf(format string, err error) error {
+	outerMsg := "<nil>"
+	if err != nil {
+		outerMsg = err.Error()
+	}
+
+	outer := errors.New(strings.Replace(
+		format, "{{err}}", outerMsg, -1))
+
+	return Wrap(outer, err)
+}
+
+// Contains checks if the given error contains an error with the
+// message msg. If err is not a wrapped error, this will always return
+// false unless the error itself happens to match this msg.
+func Contains(err error, msg string) bool {
+	return len(GetAll(err, msg)) > 0
+}
+
+// ContainsType checks if the given error contains an error with
+// the same concrete type as v. If err is not a wrapped error, this will
+// check the err itself.
+func ContainsType(err error, v interface{}) bool {
+	return len(GetAllType(err, v)) > 0
+}
+
+// Get is the same as GetAll but returns the deepest matching error.
+func Get(err error, msg string) error {
+	es := GetAll(err, msg)
+	if len(es) > 0 {
+		return es[len(es)-1]
+	}
+
+	return nil
+}
+
+// GetType is the same as GetAllType but returns the deepest matching error.
+func GetType(err error, v interface{}) error {
+	es := GetAllType(err, v)
+	if len(es) > 0 {
+		return es[len(es)-1]
+	}
+
+	return nil
+}
+
+// GetAll gets all the errors that might be wrapped in err with the
+// given message. The order of the errors is such that the outermost
+// matching error (the most recent wrap) is index zero, and so on.
+func GetAll(err error, msg string) []error {
+	var result []error
+
+	Walk(err, func(err error) {
+		if err.Error() == msg {
+			result = append(result, err)
+		}
+	})
+
+	return result
+}
+
+// GetAllType gets all the errors that are the same type as v.
+//
+// The order of the return value is the same as described in GetAll.
+func GetAllType(err error, v interface{}) []error {
+	var result []error
+
+	var search string
+	if v != nil {
+		search = reflect.TypeOf(v).String()
+	}
+	Walk(err, func(err error) {
+		var needle string
+		if err != nil {
+			needle = reflect.TypeOf(err).String()
+		}
+
+		if needle == search {
+			result = append(result, err)
+		}
+	})
+
+	return result
+}
+
+// Walk walks all the wrapped errors in err and calls the callback. If
+// err isn't a wrapped error, this will be called once for err. If err
+// is a wrapped error, the callback will be called for both the wrapper
+// that implements error as well as the wrapped error itself.
+func Walk(err error, cb WalkFunc) {
+	if err == nil {
+		return
+	}
+
+	switch e := err.(type) {
+	case *wrappedError:
+		cb(e.Outer)
+		Walk(e.Inner, cb)
+	case Wrapper:
+		cb(err)
+
+		for _, err := range e.WrappedErrors() {
+			Walk(err, cb)
+		}
+	default:
+		cb(err)
+	}
+}
+
+// wrappedError is an implementation of error that has both the
+// outer and inner errors.
+type wrappedError struct {
+	Outer error
+	Inner error
+}
+
+func (w *wrappedError) Error() string {
+	return w.Outer.Error()
+}
+
+func (w *wrappedError) WrappedErrors() []error {
+	return []error{w.Outer, w.Inner}
+}
diff --git a/vendor/github.com/hashicorp/errwrap/go.mod b/vendor/github.com/hashicorp/errwrap/go.mod
new file mode 100644
index 00000000..c9b84022
--- /dev/null
+++ b/vendor/github.com/hashicorp/errwrap/go.mod
@@ -0,0 +1 @@
+module github.com/hashicorp/errwrap
diff --git a/vendor/github.com/hashicorp/go-multierror/.travis.yml b/vendor/github.com/hashicorp/go-multierror/.travis.yml
new file mode 100644
index 00000000..24b80388
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/.travis.yml
@@ -0,0 +1,12 @@
+sudo: false
+
+language: go
+
+go:
+  - 1.x
+
+branches:
+  only:
+    - master
+
+script: env GO111MODULE=on make test testrace
diff --git a/vendor/github.com/hashicorp/go-multierror/LICENSE b/vendor/github.com/hashicorp/go-multierror/LICENSE
new file mode 100644
index 00000000..82b4de97
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/LICENSE
@@ -0,0 +1,353 @@
+Mozilla Public License, version 2.0
+
+1. Definitions
+
+1.1. “Contributor”
+
+     means each individual or legal entity that creates, contributes to the
+     creation of, or owns Covered Software.
+
+1.2. “Contributor Version”
+
+     means the combination of the Contributions of others (if any) used by a
+     Contributor and that particular Contributor’s Contribution.
+
+1.3. “Contribution”
+
+     means Covered Software of a particular Contributor.
+
+1.4. “Covered Software”
+
+     means Source Code Form to which the initial Contributor has attached the
+     notice in Exhibit A, the Executable Form of such Source Code Form, and
+     Modifications of such Source Code Form, in each case including portions
+     thereof.
+
+1.5. “Incompatible With Secondary Licenses”
+     means
+
+     a. that the initial Contributor has attached the notice described in
+        Exhibit B to the Covered Software; or
+
+     b. that the Covered Software was made available under the terms of version
+        1.1 or earlier of the License, but not also under the terms of a
+        Secondary License.
+
+1.6. “Executable Form”
+
+     means any form of the work other than Source Code Form.
+
+1.7. “Larger Work”
+
+     means a work that combines Covered Software with other material, in a separate
+     file or files, that is not Covered Software.
+
+1.8. “License”
+
+     means this document.
+
+1.9. “Licensable”
+
+     means having the right to grant, to the maximum extent possible, whether at the
+     time of the initial grant or subsequently, any and all of the rights conveyed by
+     this License.
+
+1.10. “Modifications”
+
+     means any of the following:
+
+     a. any file in Source Code Form that results from an addition to, deletion
+        from, or modification of the contents of Covered Software; or
+
+     b. any new file in Source Code Form that contains any Covered Software.
+
+1.11. “Patent Claims” of a Contributor
+
+      means any patent claim(s), including without limitation, method, process,
+      and apparatus claims, in any patent Licensable by such Contributor that
+      would be infringed, but for the grant of the License, by the making,
+      using, selling, offering for sale, having made, import, or transfer of
+      either its Contributions or its Contributor Version.
+
+1.12. “Secondary License”
+
+      means either the GNU General Public License, Version 2.0, the GNU Lesser
+      General Public License, Version 2.1, the GNU Affero General Public
+      License, Version 3.0, or any later versions of those licenses.
+
+1.13. “Source Code Form”
+
+      means the form of the work preferred for making modifications.
+
+1.14. “You” (or “Your”)
+
+      means an individual or a legal entity exercising rights under this
+      License. For legal entities, “You” includes any entity that controls, is
+      controlled by, or is under common control with You. For purposes of this
+      definition, “control” means (a) the power, direct or indirect, to cause
+      the direction or management of such entity, whether by contract or
+      otherwise, or (b) ownership of more than fifty percent (50%) of the
+      outstanding shares or beneficial ownership of such entity.
+
+
+2. License Grants and Conditions
+
+2.1. Grants
+
+     Each Contributor hereby grants You a world-wide, royalty-free,
+     non-exclusive license:
+
+     a. under intellectual property rights (other than patent or trademark)
+        Licensable by such Contributor to use, reproduce, make available,
+        modify, display, perform, distribute, and otherwise exploit its
+        Contributions, either on an unmodified basis, with Modifications, or as
+        part of a Larger Work; and
+
+     b. under Patent Claims of such Contributor to make, use, sell, offer for
+        sale, have made, import, and otherwise transfer either its Contributions
+        or its Contributor Version.
+
+2.2. Effective Date
+
+     The licenses granted in Section 2.1 with respect to any Contribution become
+     effective for each Contribution on the date the Contributor first distributes
+     such Contribution.
+
+2.3. Limitations on Grant Scope
+
+     The licenses granted in this Section 2 are the only rights granted under this
+     License. No additional rights or licenses will be implied from the distribution
+     or licensing of Covered Software under this License. Notwithstanding Section
+     2.1(b) above, no patent license is granted by a Contributor:
+
+     a. for any code that a Contributor has removed from Covered Software; or
+
+     b. for infringements caused by: (i) Your and any other third party’s
+        modifications of Covered Software, or (ii) the combination of its
+        Contributions with other software (except as part of its Contributor
+        Version); or
+
+     c. under Patent Claims infringed by Covered Software in the absence of its
+        Contributions.
+
+     This License does not grant any rights in the trademarks, service marks, or
+     logos of any Contributor (except as may be necessary to comply with the
+     notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+     No Contributor makes additional grants as a result of Your choice to
+     distribute the Covered Software under a subsequent version of this License
+     (see Section 10.2) or under the terms of a Secondary License (if permitted
+     under the terms of Section 3.3).
+
+2.5. Representation
+
+     Each Contributor represents that the Contributor believes its Contributions
+     are its original creation(s) or it has sufficient rights to grant the
+     rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+     This License is not intended to limit any rights You have under applicable
+     copyright doctrines of fair use, fair dealing, or other equivalents.
+
+2.7. Conditions
+
+     Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+     Section 2.1.
+
+
+3. Responsibilities
+
+3.1. Distribution of Source Form
+
+     All distribution of Covered Software in Source Code Form, including any
+     Modifications that You create or to which You contribute, must be under the
+     terms of this License. You must inform recipients that the Source Code Form
+     of the Covered Software is governed by the terms of this License, and how
+     they can obtain a copy of this License. You may not attempt to alter or
+     restrict the recipients’ rights in the Source Code Form.
+
+3.2. Distribution of Executable Form
+
+     If You distribute Covered Software in Executable Form then:
+
+     a. such Covered Software must also be made available in Source Code Form,
+        as described in Section 3.1, and You must inform recipients of the
+        Executable Form how they can obtain a copy of such Source Code Form by
+        reasonable means in a timely manner, at a charge no more than the cost
+        of distribution to the recipient; and
+
+     b. You may distribute such Executable Form under the terms of this License,
+        or sublicense it under different terms, provided that the license for
+        the Executable Form does not attempt to limit or alter the recipients’
+        rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+     You may create and distribute a Larger Work under terms of Your choice,
+     provided that You also comply with the requirements of this License for the
+     Covered Software. If the Larger Work is a combination of Covered Software
+     with a work governed by one or more Secondary Licenses, and the Covered
+     Software is not Incompatible With Secondary Licenses, this License permits
+     You to additionally distribute such Covered Software under the terms of
+     such Secondary License(s), so that the recipient of the Larger Work may, at
+     their option, further distribute the Covered Software under the terms of
+     either this License or such Secondary License(s).
+
+3.4. Notices
+
+     You may not remove or alter the substance of any license notices (including
+     copyright notices, patent notices, disclaimers of warranty, or limitations
+     of liability) contained within the Source Code Form of the Covered
+     Software, except that You may alter any license notices to the extent
+     required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+     You may choose to offer, and to charge a fee for, warranty, support,
+     indemnity or liability obligations to one or more recipients of Covered
+     Software. However, You may do so only on Your own behalf, and not on behalf
+     of any Contributor. You must make it absolutely clear that any such
+     warranty, support, indemnity, or liability obligation is offered by You
+     alone, and You hereby agree to indemnify every Contributor for any
+     liability incurred by such Contributor as a result of warranty, support,
+     indemnity or liability terms You offer. You may include additional
+     disclaimers of warranty and limitations of liability specific to any
+     jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+
+   If it is impossible for You to comply with any of the terms of this License
+   with respect to some or all of the Covered Software due to statute, judicial
+   order, or regulation then You must: (a) comply with the terms of this License
+   to the maximum extent possible; and (b) describe the limitations and the code
+   they affect. Such description must be placed in a text file included with all
+   distributions of the Covered Software under this License. Except to the
+   extent prohibited by statute or regulation, such description must be
+   sufficiently detailed for a recipient of ordinary skill to be able to
+   understand it.
+
+5. Termination
+
+5.1. The rights granted under this License will terminate automatically if You
+     fail to comply with any of its terms. However, if You become compliant,
+     then the rights granted under this License from a particular Contributor
+     are reinstated (a) provisionally, unless and until such Contributor
+     explicitly and finally terminates Your grants, and (b) on an ongoing basis,
+     if such Contributor fails to notify You of the non-compliance by some
+     reasonable means prior to 60 days after You have come back into compliance.
+     Moreover, Your grants from a particular Contributor are reinstated on an
+     ongoing basis if such Contributor notifies You of the non-compliance by
+     some reasonable means, this is the first time You have received notice of
+     non-compliance with this License from such Contributor, and You become
+     compliant prior to 30 days after Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+     infringement claim (excluding declaratory judgment actions, counter-claims,
+     and cross-claims) alleging that a Contributor Version directly or
+     indirectly infringes any patent, then the rights granted to You by any and
+     all Contributors for the Covered Software under Section 2.1 of this License
+     shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
+     license agreements (excluding distributors and resellers) which have been
+     validly granted by You or Your distributors under this License prior to
+     termination shall survive termination.
+
+6. Disclaimer of Warranty
+
+   Covered Software is provided under this License on an “as is” basis, without
+   warranty of any kind, either expressed, implied, or statutory, including,
+   without limitation, warranties that the Covered Software is free of defects,
+   merchantable, fit for a particular purpose or non-infringing. The entire
+   risk as to the quality and performance of the Covered Software is with You.
+   Should any Covered Software prove defective in any respect, You (not any
+   Contributor) assume the cost of any necessary servicing, repair, or
+   correction. This disclaimer of warranty constitutes an essential part of this
+   License. No use of  any Covered Software is authorized under this License
+   except under this disclaimer.
+
+7. Limitation of Liability
+
+   Under no circumstances and under no legal theory, whether tort (including
+   negligence), contract, or otherwise, shall any Contributor, or anyone who
+   distributes Covered Software as permitted above, be liable to You for any
+   direct, indirect, special, incidental, or consequential damages of any
+   character including, without limitation, damages for lost profits, loss of
+   goodwill, work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses, even if such party shall have been
+   informed of the possibility of such damages. This limitation of liability
+   shall not apply to liability for death or personal injury resulting from such
+   party’s negligence to the extent applicable law prohibits such limitation.
+   Some jurisdictions do not allow the exclusion or limitation of incidental or
+   consequential damages, so this exclusion and limitation may not apply to You.
+
+8. Litigation
+
+   Any litigation relating to this License may be brought only in the courts of
+   a jurisdiction where the defendant maintains its principal place of business
+   and such litigation shall be governed by laws of that jurisdiction, without
+   reference to its conflict-of-law provisions. Nothing in this Section shall
+   prevent a party’s ability to bring cross-claims or counter-claims.
+
+9. Miscellaneous
+
+   This License represents the complete agreement concerning the subject matter
+   hereof. If any provision of this License is held to be unenforceable, such
+   provision shall be reformed only to the extent necessary to make it
+   enforceable. Any law or regulation which provides that the language of a
+   contract shall be construed against the drafter shall not be used to construe
+   this License against a Contributor.
+
+
+10. Versions of the License
+
+10.1. New Versions
+
+      Mozilla Foundation is the license steward. Except as provided in Section
+      10.3, no one other than the license steward has the right to modify or
+      publish new versions of this License. Each version will be given a
+      distinguishing version number.
+
+10.2. Effect of New Versions
+
+      You may distribute the Covered Software under the terms of the version of
+      the License under which You originally received the Covered Software, or
+      under the terms of any subsequent version published by the license
+      steward.
+
+10.3. Modified Versions
+
+      If you create software not governed by this License, and you want to
+      create a new license for such software, you may create and use a modified
+      version of this License if you rename the license and remove any
+      references to the name of the license steward (except to note that such
+      modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary Licenses
+      If You choose to distribute Source Code Form that is Incompatible With
+      Secondary Licenses under the terms of this version of the License, the
+      notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+
+      This Source Code Form is subject to the
+      terms of the Mozilla Public License, v.
+      2.0. If a copy of the MPL was not
+      distributed with this file, You can
+      obtain one at
+      http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular file, then
+You may include the notice in a location (such as a LICENSE file in a relevant
+directory) where a recipient would be likely to look for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - “Incompatible With Secondary Licenses” Notice
+
+      This Source Code Form is “Incompatible
+      With Secondary Licenses”, as defined by
+      the Mozilla Public License, v. 2.0.
diff --git a/vendor/github.com/hashicorp/go-multierror/Makefile b/vendor/github.com/hashicorp/go-multierror/Makefile
new file mode 100644
index 00000000..b97cd6ed
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/Makefile
@@ -0,0 +1,31 @@
+TEST?=./...
+
+default: test
+
+# test runs the test suite and vets the code.
+test: generate
+	@echo "==> Running tests..."
+	@go list $(TEST) \
+		| grep -v "/vendor/" \
+		| xargs -n1 go test -timeout=60s -parallel=10 ${TESTARGS}
+
+# testrace runs the race checker
+testrace: generate
+	@echo "==> Running tests (race)..."
+	@go list $(TEST) \
+		| grep -v "/vendor/" \
+		| xargs -n1 go test -timeout=60s -race ${TESTARGS}
+
+# updatedeps installs all the dependencies needed to run and build.
+updatedeps:
+	@sh -c "'${CURDIR}/scripts/deps.sh' '${NAME}'"
+
+# generate runs `go generate` to build the dynamically generated source files.
+generate:
+	@echo "==> Generating..."
+	@find . -type f -name '.DS_Store' -delete
+	@go list ./... \
+		| grep -v "/vendor/" \
+		| xargs -n1 go generate
+
+.PHONY: default test testrace updatedeps generate
diff --git a/vendor/github.com/hashicorp/go-multierror/README.md b/vendor/github.com/hashicorp/go-multierror/README.md
new file mode 100644
index 00000000..e92fa614
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/README.md
@@ -0,0 +1,131 @@
+# go-multierror
+
+[![Build Status](http://img.shields.io/travis/hashicorp/go-multierror.svg?style=flat-square)][travis]
+[![Go Documentation](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)][godocs]
+
+[travis]: https://travis-ci.org/hashicorp/go-multierror
+[godocs]: https://godoc.org/github.com/hashicorp/go-multierror
+
+`go-multierror` is a package for Go that provides a mechanism for
+representing a list of `error` values as a single `error`.
+
+This allows a function in Go to return an `error` that might actually
+be a list of errors. If the caller knows this, they can unwrap the
+list and access the errors. If the caller doesn't know, the error
+formats to a nice human-readable format.
+
+`go-multierror` is fully compatible with the Go standard library
+[errors](https://golang.org/pkg/errors/) package, including the
+functions `As`, `Is`, and `Unwrap`. This provides a standardized approach
+for introspecting on error values.
+
+## Installation and Docs
+
+Install using `go get github.com/hashicorp/go-multierror`.
+
+Full documentation is available at
+http://godoc.org/github.com/hashicorp/go-multierror
+
+## Usage
+
+go-multierror is easy to use and purposely built to be unobtrusive in
+existing Go applications/libraries that may not be aware of it.
+
+**Building a list of errors**
+
+The `Append` function is used to create a list of errors. This function
+behaves a lot like the Go built-in `append` function: it doesn't matter
+if the first argument is nil, a `multierror.Error`, or any other `error`,
+the function behaves as you would expect.
+
+```go
+var result error
+
+if err := step1(); err != nil {
+	result = multierror.Append(result, err)
+}
+if err := step2(); err != nil {
+	result = multierror.Append(result, err)
+}
+
+return result
+```
+
+**Customizing the formatting of the errors**
+
+By specifying a custom `ErrorFormat`, you can customize the format
+of the `Error() string` function:
+
+```go
+var result *multierror.Error
+
+// ... accumulate errors here, maybe using Append
+
+if result != nil {
+	result.ErrorFormat = func([]error) string {
+		return "errors!"
+	}
+}
+```
+
+**Accessing the list of errors**
+
+`multierror.Error` implements `error` so if the caller doesn't know about
+multierror, it will work just fine. But if you're aware a multierror might
+be returned, you can use type switches to access the list of errors:
+
+```go
+if err := something(); err != nil {
+	if merr, ok := err.(*multierror.Error); ok {
+		// Use merr.Errors
+	}
+}
+```
+
+You can also use the standard [`errors.Unwrap`](https://golang.org/pkg/errors/#Unwrap)
+function. This will continue to unwrap into subsequent errors until none exist.
+
+**Extracting an error**
+
+The standard library [`errors.As`](https://golang.org/pkg/errors/#As)
+function can be used directly with a multierror to extract a specific error:
+
+```go
+// Assume err is a multierror value
+err := somefunc()
+
+// We want to know if "err" has a "RichErrorType" in it and extract it.
+var errRich RichErrorType
+if errors.As(err, &errRich) {
+	// It has it, and now errRich is populated.
+}
+```
+
+**Checking for an exact error value**
+
+Some errors are returned as exact errors such as the [`ErrNotExist`](https://golang.org/pkg/os/#pkg-variables)
+error in the `os` package. You can check if this error is present by using
+the standard [`errors.Is`](https://golang.org/pkg/errors/#Is) function.
+
+```go
+// Assume err is a multierror value
+err := somefunc()
+if errors.Is(err, os.ErrNotExist) {
+	// err contains os.ErrNotExist
+}
+```
+
+**Returning a multierror only if there are errors**
+
+If you build a `multierror.Error`, you can use the `ErrorOrNil` function
+to return an `error` implementation only if there are errors to return:
+
+```go
+var result *multierror.Error
+
+// ... accumulate errors here
+
+// Return the `error` only if errors were added to the multierror, otherwise
+// return nil since there are no errors.
+return result.ErrorOrNil()
+```
diff --git a/vendor/github.com/hashicorp/go-multierror/append.go b/vendor/github.com/hashicorp/go-multierror/append.go
new file mode 100644
index 00000000..775b6e75
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/append.go
@@ -0,0 +1,41 @@
+package multierror
+
+// Append is a helper function that will append more errors
+// onto an Error in order to create a larger multi-error.
+//
+// If err is not a multierror.Error, then it will be turned into
+// one. If any of the errs are multierr.Error, they will be flattened
+// one level into err.
+func Append(err error, errs ...error) *Error {
+	switch err := err.(type) {
+	case *Error:
+		// Typed nils can reach here, so initialize if we are nil
+		if err == nil {
+			err = new(Error)
+		}
+
+		// Go through each error and flatten
+		for _, e := range errs {
+			switch e := e.(type) {
+			case *Error:
+				if e != nil {
+					err.Errors = append(err.Errors, e.Errors...)
+				}
+			default:
+				if e != nil {
+					err.Errors = append(err.Errors, e)
+				}
+			}
+		}
+
+		return err
+	default:
+		newErrs := make([]error, 0, len(errs)+1)
+		if err != nil {
+			newErrs = append(newErrs, err)
+		}
+		newErrs = append(newErrs, errs...)
+
+		return Append(&Error{}, newErrs...)
+	}
+}
diff --git a/vendor/github.com/hashicorp/go-multierror/flatten.go b/vendor/github.com/hashicorp/go-multierror/flatten.go
new file mode 100644
index 00000000..aab8e9ab
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/flatten.go
@@ -0,0 +1,26 @@
+package multierror
+
+// Flatten flattens the given error, merging any *Errors together into
+// a single *Error.
+func Flatten(err error) error {
+	// If it isn't an *Error, just return the error as-is
+	if _, ok := err.(*Error); !ok {
+		return err
+	}
+
+	// Otherwise, make the result and flatten away!
+	flatErr := new(Error)
+	flatten(err, flatErr)
+	return flatErr
+}
+
+func flatten(err error, flatErr *Error) {
+	switch err := err.(type) {
+	case *Error:
+		for _, e := range err.Errors {
+			flatten(e, flatErr)
+		}
+	default:
+		flatErr.Errors = append(flatErr.Errors, err)
+	}
+}
diff --git a/vendor/github.com/hashicorp/go-multierror/format.go b/vendor/github.com/hashicorp/go-multierror/format.go
new file mode 100644
index 00000000..47f13c49
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/format.go
@@ -0,0 +1,27 @@
+package multierror
+
+import (
+	"fmt"
+	"strings"
+)
+
+// ErrorFormatFunc is a function callback that is called by Error to
+// turn the list of errors into a string.
+type ErrorFormatFunc func([]error) string
+
+// ListFormatFunc is a basic formatter that outputs the number of errors
+// that occurred along with a bullet point list of the errors.
+func ListFormatFunc(es []error) string {
+	if len(es) == 1 {
+		return fmt.Sprintf("1 error occurred:\n\t* %s\n\n", es[0])
+	}
+
+	points := make([]string, len(es))
+	for i, err := range es {
+		points[i] = fmt.Sprintf("* %s", err)
+	}
+
+	return fmt.Sprintf(
+		"%d errors occurred:\n\t%s\n\n",
+		len(es), strings.Join(points, "\n\t"))
+}
diff --git a/vendor/github.com/hashicorp/go-multierror/go.mod b/vendor/github.com/hashicorp/go-multierror/go.mod
new file mode 100644
index 00000000..0afe8e6f
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/go.mod
@@ -0,0 +1,5 @@
+module github.com/hashicorp/go-multierror
+
+go 1.14
+
+require github.com/hashicorp/errwrap v1.0.0
diff --git a/vendor/github.com/hashicorp/go-multierror/go.sum b/vendor/github.com/hashicorp/go-multierror/go.sum
new file mode 100644
index 00000000..e8238e9e
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/go.sum
@@ -0,0 +1,2 @@
+github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
+github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
diff --git a/vendor/github.com/hashicorp/go-multierror/group.go b/vendor/github.com/hashicorp/go-multierror/group.go
new file mode 100644
index 00000000..9c29efb7
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/group.go
@@ -0,0 +1,38 @@
+package multierror
+
+import "sync"
+
+// Group is a collection of goroutines which return errors that need to be
+// coalesced.
+type Group struct {
+	mutex sync.Mutex
+	err   *Error
+	wg    sync.WaitGroup
+}
+
+// Go calls the given function in a new goroutine.
+//
+// If the function returns an error it is added to the group multierror which
+// is returned by Wait.
+func (g *Group) Go(f func() error) {
+	g.wg.Add(1)
+
+	go func() {
+		defer g.wg.Done()
+
+		if err := f(); err != nil {
+			g.mutex.Lock()
+			g.err = Append(g.err, err)
+			g.mutex.Unlock()
+		}
+	}()
+}
+
+// Wait blocks until all function calls from the Go method have returned, then
+// returns the multierror.
+func (g *Group) Wait() *Error {
+	g.wg.Wait()
+	g.mutex.Lock()
+	defer g.mutex.Unlock()
+	return g.err
+}
diff --git a/vendor/github.com/hashicorp/go-multierror/multierror.go b/vendor/github.com/hashicorp/go-multierror/multierror.go
new file mode 100644
index 00000000..d05dd926
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/multierror.go
@@ -0,0 +1,118 @@
+package multierror
+
+import (
+	"errors"
+	"fmt"
+)
+
+// Error is an error type to track multiple errors. This is used to
+// accumulate errors in cases and return them as a single "error".
+type Error struct {
+	Errors      []error
+	ErrorFormat ErrorFormatFunc
+}
+
+func (e *Error) Error() string {
+	fn := e.ErrorFormat
+	if fn == nil {
+		fn = ListFormatFunc
+	}
+
+	return fn(e.Errors)
+}
+
+// ErrorOrNil returns an error interface if this Error represents
+// a list of errors, or returns nil if the list of errors is empty. This
+// function is useful at the end of accumulation to make sure that the value
+// returned represents the existence of errors.
+func (e *Error) ErrorOrNil() error {
+	if e == nil {
+		return nil
+	}
+	if len(e.Errors) == 0 {
+		return nil
+	}
+
+	return e
+}
+
+func (e *Error) GoString() string {
+	return fmt.Sprintf("*%#v", *e)
+}
+
+// WrappedErrors returns the list of errors that this Error is wrapping.
+// It is an implementation of the errwrap.Wrapper interface so that
+// multierror.Error can be used with that library.
+//
+// This method is not safe to be called concurrently and is no different
+// than accessing the Errors field directly. It is implemented only to
+// satisfy the errwrap.Wrapper interface.
+func (e *Error) WrappedErrors() []error {
+	return e.Errors
+}
+
+// Unwrap returns an error from Error (or nil if there are no errors).
+// This error returned will further support Unwrap to get the next error,
+// etc. The order will match the order of Errors in the multierror.Error
+// at the time of calling.
+//
+// The resulting error supports errors.As/Is/Unwrap so you can continue
+// to use the stdlib errors package to introspect further.
+//
+// This will perform a shallow copy of the errors slice. Any errors appended
+// to this error after calling Unwrap will not be available until a new
+// Unwrap is called on the multierror.Error.
+func (e *Error) Unwrap() error {
+	// If we have no errors then we do nothing
+	if e == nil || len(e.Errors) == 0 {
+		return nil
+	}
+
+	// If we have exactly one error, we can just return that directly.
+	if len(e.Errors) == 1 {
+		return e.Errors[0]
+	}
+
+	// Shallow copy the slice
+	errs := make([]error, len(e.Errors))
+	copy(errs, e.Errors)
+	return chain(errs)
+}
+
+// chain implements the interfaces necessary for errors.Is/As/Unwrap to
+// work in a deterministic way with multierror. A chain tracks a list of
+// errors while accounting for the current represented error. This lets
+// Is/As be meaningful.
+//
+// Unwrap returns the next error. In the cleanest form, Unwrap would return
+// the wrapped error here but we can't do that if we want to properly
+// get access to all the errors. Instead, users are recommended to use
+// Is/As to get the correct error type out.
+//
+// Precondition: []error is non-empty (len > 0)
+type chain []error
+
+// Error implements the error interface
+func (e chain) Error() string {
+	return e[0].Error()
+}
+
+// Unwrap implements errors.Unwrap by returning the next error in the
+// chain or nil if there are no more errors.
+func (e chain) Unwrap() error {
+	if len(e) == 1 {
+		return nil
+	}
+
+	return e[1:]
+}
+
+// As implements errors.As by attempting to map to the current value.
+func (e chain) As(target interface{}) bool {
+	return errors.As(e[0], target)
+}
+
+// Is implements errors.Is by comparing the current value directly.
+func (e chain) Is(target error) bool {
+	return errors.Is(e[0], target)
+}
diff --git a/vendor/github.com/hashicorp/go-multierror/prefix.go b/vendor/github.com/hashicorp/go-multierror/prefix.go
new file mode 100644
index 00000000..5c477abe
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/prefix.go
@@ -0,0 +1,37 @@
+package multierror
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/errwrap"
+)
+
+// Prefix is a helper function that will prefix some text
+// to the given error. If the error is a multierror.Error, then
+// it will be prefixed to each wrapped error.
+//
+// This is useful to use when appending multiple multierrors
+// together in order to give better scoping.
+func Prefix(err error, prefix string) error {
+	if err == nil {
+		return nil
+	}
+
+	format := fmt.Sprintf("%s {{err}}", prefix)
+	switch err := err.(type) {
+	case *Error:
+		// Typed nils can reach here, so initialize if we are nil
+		if err == nil {
+			err = new(Error)
+		}
+
+		// Wrap each of the errors
+		for i, e := range err.Errors {
+			err.Errors[i] = errwrap.Wrapf(format, e)
+		}
+
+		return err
+	default:
+		return errwrap.Wrapf(format, err)
+	}
+}
diff --git a/vendor/github.com/hashicorp/go-multierror/sort.go b/vendor/github.com/hashicorp/go-multierror/sort.go
new file mode 100644
index 00000000..fecb14e8
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-multierror/sort.go
@@ -0,0 +1,16 @@
+package multierror
+
+// Len implements sort.Interface function for length
+func (err Error) Len() int {
+	return len(err.Errors)
+}
+
+// Swap implements sort.Interface function for swapping elements
+func (err Error) Swap(i, j int) {
+	err.Errors[i], err.Errors[j] = err.Errors[j], err.Errors[i]
+}
+
+// Less implements sort.Interface function for determining order
+func (err Error) Less(i, j int) bool {
+	return err.Errors[i].Error() < err.Errors[j].Error()
+}