vendor: update all dependencies

* Update all dependencies
  * Remove all `[[constraint]]` from Gopkg.toml
  * Add in the minimum number of `[[override]]` to build
  * Remove go get of github.com/inconshreveable/mousetrap as it is vendored
  * Update docs with new policy on constraints

vendor/github.com/aws/aws-sdk-go/service/s3/s3manager/batch.go

@@ -64,7 +64,7 @@ func (err *Error) Error() string {
 	if err.OrigErr != nil {
 		origErr = ":\n" + err.OrigErr.Error()
 	}
-	return fmt.Sprintf("failed to upload %q to %q%s",
+	return fmt.Sprintf("failed to perform batch operation on %q to %q%s",
 		aws.StringValue(err.Key),
 		aws.StringValue(err.Bucket),
 		origErr,
@@ -359,6 +359,13 @@ func initDeleteObjectsInput(o *s3.DeleteObjectInput) *s3.DeleteObjectsInput {
 	}
 }
 
+const (
+	// ErrDeleteBatchFailCode represents an error code which will be returned
+	// only when DeleteObjects.Errors has an error that does not contain a code.
+	ErrDeleteBatchFailCode       = "DeleteBatchError"
+	errDefaultDeleteBatchMessage = "failed to delete"
+)
+
 // deleteBatch will delete a batch of items in the objects parameters.
 func deleteBatch(ctx aws.Context, d *BatchDelete, input *s3.DeleteObjectsInput, objects []BatchDeleteObject) []Error {
 	errs := []Error{}
@@ -369,7 +376,16 @@ func deleteBatch(ctx aws.Context, d *BatchDelete, input *s3.DeleteObjectsInput,
 		}
 	} else if len(result.Errors) > 0 {
 		for i := 0; i < len(result.Errors); i++ {
-			errs = append(errs, newError(err, input.Bucket, result.Errors[i].Key))
+			code := ErrDeleteBatchFailCode
+			msg := errDefaultDeleteBatchMessage
+			if result.Errors[i].Message != nil {
+				msg = *result.Errors[i].Message
+			}
+			if result.Errors[i].Code != nil {
+				code = *result.Errors[i].Code
+			}
+
+			errs = append(errs, newError(awserr.New(code, msg, err), input.Bucket, result.Errors[i].Key))
 		}
 	}
 	for _, object := range objects {