message: [GCS] Typo in ConfigureGcsHook.
  This commit fixes a typo on ConfigureGcsHook that prevented its correct
  operation.
diff: @@ -120,13 +120,17 @@ class ConfigureGcsHook(training.SessionRunHook):
  def begin(self):
  if self._credentials:
  self._credentials_placeholder = array_ops.placeholder(dtypes.string)
  - self._credentials_ops = gen_gcs_config_ops.gcs_configure_credentials(
  + self._credentials_op = gen_gcs_config_ops.gcs_configure_credentials(
  self._credentials_placeholder)
  + else:
  + self._credentials_op = None
  if self._block_cache:
  self._block_cache_op = gen_gcs_config_ops.gcs_configure_block_cache(
  max_cache_size=self._block_cache.max_bytes,
  block_size=self._block_cache.block_size,
  max_staleness=self._block_cache.max_staleness)
  + else:
  + self._block_cache_op = None
  def after_create_session(self, session, coord):
  del coord
  