message: Doc: Update xla example instruction. Otherwise it fails with
  2018-08-20 08:28:40.998261: F tensorflow/compiler/xla/service/hlo_graph_dumper.cc:1431] Check failed: graph_renderer !=
  nullptr No registered renderer for the HLO graph. Use --xla_hlo_graph_path=PATH to export to local file system
  Aborted
diff: @@ -133,7 +133,7 @@ Execute the python script to train the model with XLA and turn on a debugging
  feature of XLA via an environmental variable that outputs the XLA graph.
  ```shell
  -TF_XLA_FLAGS=--xla_generate_hlo_graph=.* python mnist_softmax_xla.py
  +TF_XLA_FLAGS="--xla_hlo_graph_path=/tmp --xla_generate_hlo_graph=.*" python mnist_softmax_xla.py
  ```
  Open the timeline file created (`timeline.ctf.json`). The rendered timeline
  