docker save: raw json

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
Upstream-commit: d3bc787bca62edff384e06a12224be2d982353da
Component: engine

components/engine/graph/service.go

@@ -1,7 +1,6 @@
 package graph
 
 import (
-	"encoding/json"
 	"io"
 
 	"github.com/dotcloud/docker/engine"
@@ -136,7 +135,7 @@ func (s *TagStore) CmdLookup(job *engine.Job) engine.Status {
 	name := job.Args[0]
 	if image, err := s.LookupImage(name); err == nil && image != nil {
 		if job.GetenvBool("raw") {
-			b, err := json.Marshal(image)
+			b, err := image.RawJson()
 			if err != nil {
 				return job.Error(err)
 			}