Vendor after merging mtrmac/image:ParseNormalizedNamed

… and use the master branch of docker/distribution which provides
docker/distribution/reference.ParseNormalizedNamed.

vendor/github.com/docker/distribution/blobs.go

@@ -8,8 +8,8 @@ import (
 	"time"
 
 	"github.com/docker/distribution/context"
-	"github.com/docker/distribution/digest"
 	"github.com/docker/distribution/reference"
+	"github.com/opencontainers/go-digest"
 )
 
 var (
@@ -192,6 +192,18 @@ type BlobCreateOption interface {
 	Apply(interface{}) error
 }
 
+// CreateOptions is a collection of blob creation modifiers relevant to general
+// blob storage intended to be configured by the BlobCreateOption.Apply method.
+type CreateOptions struct {
+	Mount struct {
+		ShouldMount bool
+		From        reference.Canonical
+		// Stat allows to pass precalculated descriptor to link and return.
+		// Blob access check will be skipped if set.
+		Stat *Descriptor
+	}
+}
+
 // BlobWriter provides a handle for inserting data into a blob store.
 // Instances should be obtained from BlobWriteService.Writer and
 // BlobWriteService.Resume. If supported by the store, a writer can be