Fixes new response from CMS admin.

New response contains data object, e.g.:

```js
{'url': u'/admin/cms/page/edit-plugin/351/', 'breadcrumb': [{'url': u'/admin/cms/page/edit-plugin/81/', 'title': u'Text'}, {'url': u'/admin/cms/page/edit-plugin/351/', 'title': u'L\xe4nk'}]}
```

Related to #33