[VOL-4291] Rw-core updates for gRPC migration

Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/grpc-ecosystem/grpc-gateway/runtime/convert.go b/vendor/github.com/grpc-ecosystem/grpc-gateway/runtime/convert.go
index a5b3bd6..2c27934 100644
--- a/vendor/github.com/grpc-ecosystem/grpc-gateway/runtime/convert.go
+++ b/vendor/github.com/grpc-ecosystem/grpc-gateway/runtime/convert.go
@@ -206,16 +206,22 @@
 
 // Timestamp converts the given RFC3339 formatted string into a timestamp.Timestamp.
 func Timestamp(val string) (*timestamp.Timestamp, error) {
-	var r *timestamp.Timestamp
-	err := jsonpb.UnmarshalString(val, r)
-	return r, err
+	var r timestamp.Timestamp
+	err := jsonpb.UnmarshalString(val, &r)
+	if err != nil {
+		return nil, err
+	}
+	return &r, nil
 }
 
 // Duration converts the given string into a timestamp.Duration.
 func Duration(val string) (*duration.Duration, error) {
-	var r *duration.Duration
-	err := jsonpb.UnmarshalString(val, r)
-	return r, err
+	var r duration.Duration
+	err := jsonpb.UnmarshalString(val, &r)
+	if err != nil {
+		return nil, err
+	}
+	return &r, nil
 }
 
 // Enum converts the given string into an int32 that should be type casted into the