message: Fix python3 issue with iterators
  Summary: map() returns an iterator, which isn't countable
  Test Plan: None
  Reviewers: georgep
diff: @@ -131,7 +131,7 @@ def move_variable_initialization_to_cpu(graph=None):
  graph = ops.get_default_graph()
  init_ops = []
  - dep_ops = map(lambda x:x.initializer.inputs[1].op, graph.get_collection('variables'))
  + dep_ops = list(map(lambda x:x.initializer.inputs[1].op, graph.get_collection('variables')))
  visited = set()
  while len(dep_ops) > 0:
  