message: In multi_worker_training_state.py, check model's attr CKPT_SAVED_EPOCH exists before deleting it to fix AttributeError. The AttributeError could happen if the program had a failure before the model's attribute was added.
diff: @@ -170,6 +170,9 @@ class MultiWorkerTrainingState(object):
  successfully finishes.
  """
  self._assert_in_multi_worker_mode()
  + # Model may not have such attr if there was a failure before the attr was
  + # added to the model
  + if hasattr(self._model, CKPT_SAVED_EPOCH):
  tracking.AutoTrackable.__delattr__(self._model, CKPT_SAVED_EPOCH)
  if multi_worker_util.should_save_checkpoint():
  _remove_dir(self._backup_dir)
  