Add stable branch check jobs

designate-tempest-plugin is a branchless repository (no stable branches),
so we should have check jobs that make sure new tests don't artificially
fail when run against the stable branches.

Change-Id: I6529af7f4e2222a2cf4a1f937601d7be119e182a

.zuul.yaml

@@ -1,3 +1,23 @@
+- job:
+    name: designate-bind9-stable-xena
+    parent: designate-bind9
+    override-checkout: stable/xena
+
+- job:
+    name: designate-bind9-stable-wallaby
+    parent: designate-bind9
+    override-checkout: stable/wallaby
+
+- job:
+    name: designate-bind9-stable-victoria
+    parent: designate-bind9
+    override-checkout: stable/victoria
+
+- job:
+    name: designate-bind9-stable-ussuri
+    parent: designate-bind9
+    override-checkout: stable/ussuri
+
 - project:
     templates:
       - designate-devstack-jobs
@@ -7,6 +27,10 @@
       - release-notes-jobs-python3
     check:
       jobs:
+        - designate-bind9-stable-xena
+        - designate-bind9-stable-wallaby
+        - designate-bind9-stable-victoria
+        - designate-bind9-stable-ussuri
         - neutron-tempest-plugin-designate-scenario
     gate:
       queue: designate