The notify "Restart tacker containers" is not correct

No handler named "Restart tacker containers", and we should restart
the tacker container according to the context

Change-Id: Idad8843e85eeb536d7abf8332606801f5b6e78ce
Closes-Bug: #1700007

ansible/roles/tacker/tasks/config.yml

@@ -57,9 +57,9 @@
     - tacker_policy.stat.exists
   with_dict: "{{ tacker_services }}"
   notify:
-    - Restart tacker containers
+    - Restart tacker container
 
-- name: Check tacker containers
+- name: Check tacker container
   kolla_docker:
     action: "compare_container"
     name: "{{ item.value.container_name }}"