message: Install the latest tf-estimator-nightly in the RBE images.
diff: @@ -128,8 +128,8 @@ pip2 install --upgrade h5py==2.8.0
  pip3 install --upgrade h5py==2.8.0
  # Estimator
  -pip2 install tf-estimator-nightly==1.12.0.dev20181203 --no-deps
  -pip3 install tf-estimator-nightly==1.12.0.dev20181203 --no-deps
  +pip2 install tf-estimator-nightly --no-deps
  +pip3 install tf-estimator-nightly --no-deps
  # Argparse
  pip2 install --upgrade argparse
  