message: Modified dtype error info in ArrowDataset
diff: @@ -40,7 +40,7 @@ Status GetTensorFlowType(std::shared_ptr<::arrow::DataType> dtype,
  ::arrow::Status status =
  ::arrow::adapters::tensorflow::GetTensorFlowType(dtype, out);
  if (!status.ok()) {
  - return errors::InvalidArgument("arrow data type ", dtype,
  + return errors::InvalidArgument("arrow data type ", dtype->name(),
  " is not supported: ", status);
  }
  return Status::OK();
  