Build multi-site on its own stable-3.4 branch

Change-Id: Id1f5f80417b75c973451b8125e3edfbce678afc7
diff --git a/jenkins/gerrit-bazel-plugin-multi-site.yaml b/jenkins/gerrit-bazel-plugin-multi-site.yaml
index ff3fdb3..3c99098 100644
--- a/jenkins/gerrit-bazel-plugin-multi-site.yaml
+++ b/jenkins/gerrit-bazel-plugin-multi-site.yaml
@@ -4,13 +4,8 @@
       - 'plugin-{name}-bazel-{branch}':
           branch:
             - master
+            - stable-3.4
             - stable-3.3
             - stable-3.2
             - stable-3.1
             - stable-2.16
-      - 'plugin-{name}-bazel-{branch}-{gerrit-branch}':
-          branch:
-            - master
-          gerrit-branch:
-            - stable-3.4
-      - 'plugin-{name}-verifier'