message: Fix mediaStream priority initialization
diff: @@ -215,7 +215,7 @@ NAN_METHOD(MediaStream::New) {
  if (info.Length() > 8) {
  Nan::Utf8String paramPriority(Nan::To<v8::String>(info[8]).ToLocalChecked());
  priority = std::string(*paramPriority);
  - if (priority == "undefined") {
  + if (priority == "undefined" || priority == "") {
  priority = "default";
  }
  }
  