Merge "CI: only run cells job on changes to nova role" into stable/wallaby

Author: Zuul

zuul.d/base.yaml

@@ -191,6 +191,9 @@
     name: kolla-ansible-cells-base
     parent: kolla-ansible-base
     voting: false
+    files:
+      - ^ansible/roles/nova/
+      - ^tests/test-core-openstack.sh
     vars:
       scenario: cells