Update godeps

vendor/google.golang.org/grpc/metadata/metadata.go

@@ -60,15 +60,21 @@ func encodeKeyValue(k, v string) (string, string) {
 
 // DecodeKeyValue returns the original key and value corresponding to the
 // encoded data in k, v.
+// If k is a binary header and v contains comma, v is split on comma before decoded,
+// and the decoded v will be joined with comma before returned.
 func DecodeKeyValue(k, v string) (string, string, error) {
 	if !strings.HasSuffix(k, binHdrSuffix) {
 		return k, v, nil
 	}
-	val, err := base64.StdEncoding.DecodeString(v)
-	if err != nil {
-		return "", "", err
+	vvs := strings.Split(v, ",")
+	for i, vv := range vvs {
+		val, err := base64.StdEncoding.DecodeString(vv)
+		if err != nil {
+			return "", "", err
+		}
+		vvs[i] = string(val)
 	}
-	return k, string(val), nil
+	return k, strings.Join(vvs, ","), nil
 }
 
 // MD is a mapping from metadata keys to values. Users should use the following