message: Fixed the typo in RunConfig pydoc.
diff: @@ -345,7 +345,7 @@ class RunConfig(object):
  os.environ['TF_CONFIG'] = json.dumps(
  {'cluster': cluster,
  'task': {'type': 'worker', 'index': 1}})
  - config = ClusterConfig()
  + config = RunConfig()
  assert config.master == 'host4:2222'
  assert config.task_id == 1
  assert config.num_ps_replicas == 2
  @@ -363,7 +363,7 @@ class RunConfig(object):
  os.environ['TF_CONFIG'] = json.dumps(
  {'cluster': cluster,
  'task': {'type': 'chief', 'index': 0}})
  - config = ClusterConfig()
  + config = RunConfig()
  assert config.master == 'host0:2222'
  assert config.task_id == 0
  assert config.num_ps_replicas == 2
  @@ -381,7 +381,7 @@ class RunConfig(object):
  os.environ['TF_CONFIG'] = json.dumps(
  {'cluster': cluster,
  'task': {'type': 'evaluator', 'index': 0}})
  - config = ClusterConfig()
  + config = RunConfig()
  assert config.master == ''
  assert config.evaluator_master == ''
  assert config.task_id == 0
  