message: Fix session_list_devices_test
  Fixes
diff: @@ -39,7 +39,6 @@ class SessionListDevicesTestMethods(object):
  devices = sess.list_devices()
  self.assertTrue('/job:localhost/replica:0/task:0/device:CPU:0' in set(
  [d.name for d in devices]), devices)
  - self.assertGreaterEqual(1, len(devices), devices)
  def testInvalidDeviceNumber(self):
  opts = tf_session.TF_NewSessionOptions()
  @@ -65,7 +64,6 @@ class SessionListDevicesTestMethods(object):
  devices = sess.list_devices()
  self.assertTrue('/job:local/replica:0/task:0/device:CPU:0' in set(
  [d.name for d in devices]), devices)
  - self.assertGreaterEqual(1, len(devices), devices)
  def testListDevicesClusterSpecPropagation(self):
  server1 = server_lib.Server.create_local_server()
  @@ -84,7 +82,6 @@ class SessionListDevicesTestMethods(object):
  '/job:worker/replica:0/task:0/device:CPU:0' in device_names)
  self.assertTrue(
  '/job:worker/replica:0/task:1/device:CPU:0' in device_names)
  - self.assertGreaterEqual(2, len(devices), devices)
  class SessionListDevicesTest(SessionListDevicesTestMethods,
  