message: Fix the way we set the stream priority in ErizoAPI
diff: @@ -213,7 +213,7 @@ NAN_METHOD(MediaStream::New) {
  std::string priority = "default";
  if (info.Length() > 8) {
  - Nan::Utf8String paramPriority(Nan::To<v8::String>(info[7]).ToLocalChecked());
  + Nan::Utf8String paramPriority(Nan::To<v8::String>(info[8]).ToLocalChecked());
  priority = std::string(*paramPriority);
  if (priority == "undefined") {
  priority = "default";
  