Removes ignored const from return type (#2915)
Removes ignored const from return type (#2915)

See https://github.com/google/protobuf/issues/2425
google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf