message: Fix TFX breakage when exporting a SavedModel using a tf.contrib.learn estimator.
diff: @@ -1095,6 +1095,15 @@ class BaseEstimator(sklearn.BaseEstimator, evaluable.Evaluable,
  _, loss = mon_sess.run([model_fn_ops.train_op, model_fn_ops.loss])
  return loss
  + def latest_checkpoint(self):
  + """Finds the filename of the latest saved checkpoint file in `model_dir`.
  +
  + Returns:
  + The full path to the latest checkpoint or `None` if no checkpoint was
  + found.
  + """
  + return checkpoint_management.latest_checkpoint(self.model_dir)
  +
  def _identity_feature_engineering_fn(features, labels):
  return features, labels
  