bifrost: Use the combined Ironic service instead of API+conductor

Fix bifrost stop.yml after I9faecfe6ece6d3c35396e3378c1e3930a487e130

Change-Id: I850cbbb83d10b1518cc73612a591b160c2d49f1c

ansible/roles/bifrost/tasks/stop.yml

@@ -14,8 +14,7 @@
           become: true
           command: docker exec bifrost_deploy systemctl stop {{ item }}.service
           with_items:
-            - ironic-api
-            - ironic-conductor
+            - ironic
             - ironic-inspector
             - mariadb
             - nginx