Build admin-console plugin on its own stable-3.1 branch

Change-Id: Ia17e2a1ab4735472feb6b7166994c4788778a4a0
diff --git a/jenkins/gerrit-bazel-plugin-admin-console.yaml b/jenkins/gerrit-bazel-plugin-admin-console.yaml
index 19b8af0..134cd43 100644
--- a/jenkins/gerrit-bazel-plugin-admin-console.yaml
+++ b/jenkins/gerrit-bazel-plugin-admin-console.yaml
@@ -7,8 +7,8 @@
           gerrit-branch:
             - master
             - stable-3.2
-            - stable-3.1
       - 'plugin-{name}-bazel-{branch}':
           branch:
+            - stable-3.1
             - stable-3.0
             - stable-2.16