message: fix(//cpp/api): set a default for calibrator
diff: @@ -215,7 +215,7 @@ struct TRTORCH_API ExtraInfo {
  /**
  * Calibration dataloaders for each input for post training quantizatiom
  */
  - nvinfer1::IInt8Calibrator* ptq_calibrator;
  + nvinfer1::IInt8Calibrator* ptq_calibrator = nullptr;
  };
  /**
  