Update the RBE hash and install golang on RBE images.

PiperOrigin-RevId: 254229393

tensorflow/tools/ci_build/Dockerfile.rbe.cpu-centos6

@@ -29,7 +29,12 @@ RUN bash install/install_yum_packages.sh
 RUN bash install/install_centos_python36.sh
 RUN bash install/install_centos_pip_packages.sh
 
-# Install a /usr/bin/python3 link.
+# Install golang.
+RUN bash install/install_golang_centos.sh
+env GOROOT=/usr/local/go
+env PATH=$GOPATH/bin:$GOROOT/bin:$PATH
+
+# Install a /usr/bin/python2 and /usr/bin/python3 link.
 # centos by default does not provide links, and instead relies on paths into
 # /opt/ to switch to alternative configurations. For bazel remote builds,
 # the python path between the local machine running bazel and the remote setup

tensorflow/tools/ci_build/install/install_golang_centos.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# Copyright 2019 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+
+set -ex
+
+GOLANG_URL="https://dl.google.com/go/go1.12.6.linux-amd64.tar.gz"
+
+
+cd /usr/src
+wget "${GOLANG_URL}"
+tar -xzf go1.12.6.linux-amd64.tar.gz
+mv go /usr/local
+rm /usr/src/go1.12.6.linux-amd64.tar.gz

third_party/toolchains/preconfig/generate/containers.bzl

@@ -4,6 +4,6 @@ container_digests = {
     "centos6": "sha256:5450c88850260a5d46f4942c3807e2240eb5e792fce5e788bacf2317309969f1",
     "cuda10.0-cudnn7-ubuntu14.04": "sha256:d433e1221f802dac393bc8652fabcc63aa46896cd920bb888ae0e2002fe6b756",
     "cuda10.0-cudnn7-centos7": "sha256:a453b7147a60928a8345689eae48916a746b3578b5e831bfa151f0529d469c88",
-    "cuda10.0-cudnn7-centos6": "sha256:a1909ba09c703340ee0074ce63dd94fe8fea48035a25264677907a609e2375e0",
+    "cuda10.0-cudnn7-centos6": "sha256:d09c12fb26fbbe8398b4973260c75172eb67d509dae9d6f4ad54279b7d6b0494",
     "cuda10.0-cudnn7-ubuntu16.04-manylinux2010": "sha256:eedcedfe63a778068bf725f9ffa425646725faac9ba96a57abfad307e832dcf9",
 }