Use Bazel for master branch and Buck for stable-*

Change-Id: I515f9b72dd4c1fb45c57217d90586bd69a7ca40e
diff --git a/jenkins/gerrit-buck-bazel-template.yaml b/jenkins/gerrit-buck-bazel-template.yaml
index 4df8273..2761dce 100644
--- a/jenkins/gerrit-buck-bazel-template.yaml
+++ b/jenkins/gerrit-buck-bazel-template.yaml
@@ -26,9 +26,9 @@
              - job-extended-read
     dsl: |
       retries = 3
+      build = "{branch}" == "master" ? "bazel" : "buck"
       parallel (
-        {{ retry ( retries ) {{ build( "Gerrit-buck-{branch}" ) }} }},
-        {{ if("{branch}" == "master") {{ retry ( retries ) {{ build( "Gerrit-bazel-{branch}" ) }} }} }}
+        {{ retry ( retries ) {{ build( "Gerrit-$build-{branch}" ) }} }}
       )
 
 - job-template:
@@ -140,7 +140,6 @@
 - project:
     name: Gerrit-buck
     branch:
-      - master
       - stable-2.13
       - stable-2.12
       - stable-2.11