message: Remove code owners for tf.contrib modules
diff: /tensorflow/tensorboard/ @jart
  /tensorflow/tools/docs/ @markdaoust
  -# contrib
  -
  -# NEED OWNER: /tensorflow/contrib/all_reduce
  -/tensorflow/contrib/autograph/ @mdanatg @kkimdev
  -/tensorflow/contrib/batching/ @alextp @chrisolston
  -/tensorflow/contrib/bayesflow/ @ebrevdo @rsepassi @jvdillon
  -/tensorflow/contrib/boosted_trees/ @sshrdp @yk5 @nataliaponomareva
  -/tensorflow/contrib/checkpoint/ @allenlavoie
  -/tensorflow/contrib/contrib/cluster_resolver/ @frankchn
  -/tensorflow/contrib/cmake/ @mrry
  -/tensorflow/contrib/copy_graph/ @tucker @poxvoculi
  -/tensorflow/contrib/crf/ @kentonl
  -/tensorflow/contrib/data/ @mrry
  -/tensorflow/tensorflow/contrib/distribute @joshl @priyag @sourabhbajaj @frankchn
  -/tensorflow/contrib/distributions/ @jvdillon @langmore @rsepassi
  -/tensorflow/contrib/eager @jaingaurav @alextp
  -/tensorflow/contrib/factorization/ @agarwal-ashish @xavigonzalvo
  -/tensorflow/contrib/ffmpeg/ @fredbertsch
  -/tensorflow/contrib/framework/ @ebrevdo
  -/tensorflow/contrib/graph_editor/ @purpledog
  -# NEED OWNER: /tensorflow/contrib/grid_rnn/
  -/tensorflow/contrib/hadoop @yongtang
  -/tensorflow/contrib/hvx/ @satok16
  -/tensorflow/contrib/integrate/ @shoyer
  -/tensorflow/contrib/kernel_methods/ @petrosmol
  -/tensorflow/contrib/ios_examples/ @petewarden
  -/tensorflow/contrib/labeled_tensor/ @shoyer
  -/tensorflow/contrib/layers/ @fchollet @martinwicke
  -/tensorflow/contrib/learn/ @martinwicke @ispirmustafa @alextp
  -/tensorflow/contrib/linear_optimizer/ @petrosmol @andreasst @katsiapis
  -/tensorflow/contrib/lookup/ @ysuematsu @andreasst
  -/tensorflow/contrib/losses/ @alextp @ispirmustafa
  -/tensorflow/contrib/makefile/ @petewarden @satok16 @wolffg
  -/tensorflow/contrib/metrics/ @alextp @honkentuber @ispirmustafa
  -/tensorflow/contrib/opt/ @strategist333 @alextp
  -/tensorflow/contrib/pi_examples/ @maciekcc
  -/tensorflow/contrib/quantization/ @petewarden
  -/tensorflow/contrib/rnn/ @ebrevdo @scottzhu
  -/tensorflow/contrib/saved_model/ @nfiedel @sukritiramesh @allenlavoie
  -/tensorflow/contrib/seq2seq/ @ebrevdo @lmthang
  -/tensorflow/contrib/session_bundle/ @nfiedel @sukritiramesh
  -/tensorflow/contrib/slim/ @sguada @thenbasilmanran
  -/tensorflow/contrib/stateless/ @girving @alextp
  -/tensorflow/contrib/tensor_forest/ @gilberthendry @thomascolthurst @yupbank
  -/tensorflow/contrib/tensorrt/ @aaroey @smit-hinsu @azaks2
  -# NEED OWNER: /tensorflow/contrib/testing/
  -/tensorflow/contrib/timeseries/ @allenlavoie
  -/tensorflow/contrib/tpu/ @frankchn @saeta @jhseu @sourabhbajaj
  -/tensorflow/contrib/training/ @joel-shor @ebrevdo
  -/tensorflow/contrib/util/ @sherrym
  -
  /third_party/systemlibs/ @perfinion
  