Align code to match order of fields

This is just cosmetic; alighn the fields with the order in which they appear
in the struct (and JSON output).

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

manifest/schema1/config_builder_test.go

@@ -29,9 +29,9 @@ func (bs *mockBlobService) Stat(ctx context.Context, dgst digest.Digest) (distri
 
 func (bs *mockBlobService) Put(ctx context.Context, mediaType string, p []byte) (distribution.Descriptor, error) {
 	d := distribution.Descriptor{
+		MediaType: mediaType,
 		Digest:    digest.FromBytes(p),
 		Size:      int64(len(p)),
-		MediaType: mediaType,
 	}
 	bs.descriptors[d.Digest] = d
 	return d, nil

manifest/schema1/manifest.go

@@ -35,9 +35,9 @@ func init() {
 		}
 
 		desc := distribution.Descriptor{
+			MediaType: MediaTypeSignedManifest,
 			Digest:    digest.FromBytes(sm.Canonical),
 			Size:      int64(len(sm.Canonical)),
-			MediaType: MediaTypeSignedManifest,
 		}
 		return sm, desc, err
 	}