message: Use gfile.Open instead of Open for mnist reader.
  (I have mnist datasets on CNS so without this, the script fails with a FileNotFound Error.
diff: @@ -27,6 +27,7 @@ from six.moves import xrange # pylint: disable=redefined-builtin
  from tensorflow.contrib.learn.python.learn.datasets import base
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import random_seed
  +from tensorflow.python.platform import gfile
  # CVDF mirror of http://yann.lecun.com/exdb/mnist/
  SOURCE_URL = 'https://storage.googleapis.com/cvdf-datasets/mnist/'
  @@ -233,22 +234,22 @@ def read_data_sets(train_dir,
  local_file = base.maybe_download(TRAIN_IMAGES, train_dir,
  SOURCE_URL + TRAIN_IMAGES)
  - with open(local_file, 'rb') as f:
  + with gfile.Open(local_file, 'rb') as f:
  train_images = extract_images(f)
  local_file = base.maybe_download(TRAIN_LABELS, train_dir,
  SOURCE_URL + TRAIN_LABELS)
  - with open(local_file, 'rb') as f:
  + with gfile.Open(local_file, 'rb') as f:
  train_labels = extract_labels(f, one_hot=one_hot)
  local_file = base.maybe_download(TEST_IMAGES, train_dir,
  SOURCE_URL + TEST_IMAGES)
  - with open(local_file, 'rb') as f:
  + with gfile.Open(local_file, 'rb') as f:
  test_images = extract_images(f)
  local_file = base.maybe_download(TEST_LABELS, train_dir,
  SOURCE_URL + TEST_LABELS)
  - with open(local_file, 'rb') as f:
  + with gfile.Open(local_file, 'rb') as f:
  test_labels = extract_labels(f, one_hot=one_hot)
  if not 0 <= validation_size <= len(train_images):
  