message: Use the default rewriter config instead of a custom one
diff: @@ -55,11 +55,6 @@ def PlaceGraph(metagraph,
  # Optimize the metagraph to speedup the placement
  rewriter_config = rewriter_config_pb2.RewriterConfig()
  - rewriter_config.optimizers.append("pruning")
  - rewriter_config.optimizers.append("constfold")
  - rewriter_config.optimizers.append("arithmetic")
  - rewriter_config.optimizers.append("dependency")
  - rewriter_config.optimizers.append("pruning")
  optimized_graph = tf_optimizer.OptimizeGraph(
  rewriter_config, metagraph, verbose=verbose, cluster=cluster)
  optimized_metagraph = meta_graph_pb2.MetaGraphDef()
  