Ignore objects in inconsistent state during listing

Change-Id: I3d087c26678f2e753959d34550350ee101b881a6
Closes-Bug: 1464901
(cherry picked from commit bb1af78)

src/config/api-server/vnc_cfg_api_server.py

@@ -1291,6 +1291,11 @@ def _list_collection(self, obj_type, parent_uuids=None,
                 obj_dict['href'] = self.generate_url(
                                         obj_type, obj_result['uuid'])
                 obj_dict.update(obj_result)
+                if 'id_perms' not in obj_dict:
+                    # It is possible that the object was deleted, but received
+                    # an update after that. We need to ignore it for now. In
+                    # future, we should clean up such stale objects
+                    continue
                 if (obj_dict['id_perms'].get('user_visible', True) or
                     self.is_admin_request()):
                     obj_dicts.append({obj_type: obj_dict})