Build metrics-reporter-graphite plugin on stable-2.14

Change-Id: Id773c07ffb6a41f813450825993438c736c690e3
diff --git a/jenkins/gerrit-buck-bazel-plugin-metrics-reporter-graphite.yaml b/jenkins/gerrit-buck-bazel-plugin-metrics-reporter-graphite.yaml
index 0eacfad..d479964 100644
--- a/jenkins/gerrit-buck-bazel-plugin-metrics-reporter-graphite.yaml
+++ b/jenkins/gerrit-buck-bazel-plugin-metrics-reporter-graphite.yaml
@@ -7,3 +7,4 @@
       - 'plugin-{name}-bazel-{branch}':
           branch:
             - master
+            - stable-2.14