Use google-java-format version 1.6 and warm caches

Visit all the active dev branches of Gerrit Code Review
(stable-2.14, stable-2.15 and master), warm caches and
use the latest and greatest of the google-java-format.

slave-bazel Docker VM is then up-to-date and with all
deps to run any dev branch validation job as quckly
as possible.

Change-Id: I14567f6f7f1234f637cbcf5806401746ca1b5892
diff --git a/jenkins-docker/slave-bazel/Dockerfile b/jenkins-docker/slave-bazel/Dockerfile
index 113062a..1a31134 100644
--- a/jenkins-docker/slave-bazel/Dockerfile
+++ b/jenkins-docker/slave-bazel/Dockerfile
@@ -21,10 +21,14 @@
 # https://github.com/google/google-java-format/pull/154
 USER jenkins
 RUN bash -c '. /usr/bin/set-java.sh 8 && \
-    cd /tmp &&  git clone --recursive https://gerrit.googlesource.com/gerrit && \
-    cd /tmp/gerrit && ( bazel build release || true ) && \
-    cd /tmp/gerrit && ./tools/setup_gjf.sh 1.3 && \
-    cd /tmp/gerrit && ./tools/setup_gjf.sh 1.5 && \
+    cd /tmp &&  git clone -b stable-2.14 --recursive https://gerrit.googlesource.com/gerrit && \
+    cd /tmp/gerrit && \
+    ./tools/setup_gjf.sh 1.3 && \
+    ./tools/setup_gjf.sh 1.5 && \
+    ./tools/setup_gjf.sh 1.6 && \
+    ( bazel build release || true ) && \
+    git checkout -f stable-2.15 && git submodule update --init && ( bazel build release || true ) && \
+    git checkout -f master && git submodule update --init && ( bazel build release || true ) && \
     cd /tmp/gerrit/tools/format && ln -s google-java-format-1.3 google-java-format && \
     cd /tmp/gerrit && mv tools/format ~ && \
     cd /tmp/gerrit && ./tools/download_file.py -o ~/format/google-java-format-1.3-all-deps.jar -u https://github.com/davido/google-java-format/releases/download/1.3-1-gec5ce10/google-java-format-1.3-1-gec5ce10-all-deps.jar -v "65f060dc238bdd81ef029354d8e6dad6dd742ef4" && \
diff --git a/jenkins/gerrit-verifier.yaml b/jenkins/gerrit-verifier.yaml
index a079416..f2ae156 100644
--- a/jenkins/gerrit-verifier.yaml
+++ b/jenkins/gerrit-verifier.yaml
@@ -162,7 +162,7 @@
          #!/bin/bash -xe
          cd gerrit
          echo 'Running google-java-format check...'
-         git show --diff-filter=AM --name-only --pretty="" HEAD | grep java$ | xargs -r ~/format/google-java-format-1.5 -n --set-exit-if-changed
+         git show --diff-filter=AM --name-only --pretty="" HEAD | grep java$ | xargs -r ~/format/google-java-format-1.6 -n --set-exit-if-changed
       - shell: |
          #!/bin/bash -xe
          cd gerrit