Vendor updated distribution package

Another day, another revendor.

This revision of distribution is more tolerant of incorrect Content-Type
headers when fetching manifests.

Fixes #19526

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

hack/vendor.sh

@@ -46,7 +46,7 @@ clone git github.com/boltdb/bolt v1.1.0
 clone git github.com/miekg/dns 75e6e86cc601825c5dbcd4e0c209eab180997cd7
 
 # get graph and distribution packages
-clone git github.com/docker/distribution 08650825fef9f21ea819972fb2ed875c0832a255
+clone git github.com/docker/distribution c301f8ab27f4913c968b8d73a38e5dda79b9d3d7
 clone git github.com/vbatts/tar-split v0.9.11
 
 # get desired notary commit, might also need to be updated in Dockerfile

vendor/src/github.com/docker/distribution/manifests.go

@@ -2,7 +2,7 @@ package distribution
 
 import (
 	"fmt"
-	"strings"
+	"mime"
 
 	"github.com/docker/distribution/context"
 	"github.com/docker/distribution/digest"
@@ -84,19 +84,23 @@ var mappings = make(map[string]UnmarshalFunc, 0)
 // UnmarshalManifest looks up manifest unmarshall functions based on
 // MediaType
 func UnmarshalManifest(ctHeader string, p []byte) (Manifest, Descriptor, error) {
-	// Need to look up by the actual content type, not the raw contents of
+	// Need to look up by the actual media type, not the raw contents of
 	// the header. Strip semicolons and anything following them.
 	var mediatype string
-	semicolonIndex := strings.Index(ctHeader, ";")
-	if semicolonIndex != -1 {
-		mediatype = ctHeader[:semicolonIndex]
-	} else {
-		mediatype = ctHeader
+	if ctHeader != "" {
+		var err error
+		mediatype, _, err = mime.ParseMediaType(ctHeader)
+		if err != nil {
+			return nil, Descriptor{}, err
+		}
 	}
 
 	unmarshalFunc, ok := mappings[mediatype]
 	if !ok {
-		return nil, Descriptor{}, fmt.Errorf("unsupported manifest mediatype: %s", mediatype)
+		unmarshalFunc, ok = mappings[""]
+		if !ok {
+			return nil, Descriptor{}, fmt.Errorf("unsupported manifest mediatype and no default available: %s", mediatype)
+		}
 	}
 
 	return unmarshalFunc(p)