Unify the format of list response

Change the format of container_actions response for consistency
with other APIs. Right now, all the list response is of the
following format:

  {"xxx" [{...}, ...]}

Change-Id: I388548a1c15e61b62e802da634c7be8697ff05b9

api-ref/source/samples/container-actions-list-resp.json

@@ -1,4 +1,5 @@
-[
+{
+    "containerActions": [
         {
             "action": "create",
             "container_uuid": "b48316c5-71e8-45e4-9884-6c78055b9b13",
@@ -18,4 +19,4 @@
             "user_id": "22e81669093742b7a74b1d715a9a5813"
         }
     ]
-
+}

zun/api/controllers/v1/containers.py

@@ -115,7 +115,7 @@ class ContainersActionsController(base.Controller):
             context, container.uuid)
         actions = [self._format_action(action) for action in actions_raw]
 
-        return actions
+        return {"containerActions": actions}
 
     @pecan.expose('json')
     @exception.wrap_pecan_controller_exception

zun/tests/unit/api/controllers/v1/test_containers.py

@@ -1910,8 +1910,9 @@ class TestContainerActionController(api_base.FunctionalTest):
             test_container['uuid'])
 
         self.assertEqual(200, response.status_int)
-        self.assertEqual(self._format_action(test_action),
-                         self._format_action(response.json[0]))
+        self.assertEqual(
+            self._format_action(test_action),
+            self._format_action(response.json['containerActions'][0]))
 
     @mock.patch('zun.objects.Container.get_by_uuid')
     @mock.patch('zun.common.policy.enforce')