Chat code sends purge request to the URL that returns 404

Chat code sends a lot of purge requests that return 404. This obviously makes no sense and just increases the amount of items in purge requests queue to Fastly.

```json
{"url":"http:\/\/es.naruto.wikia.com\/wikia.php?controller=ChatRail&method=content","time":1394444796,"method":"ChatAjax:setUsersList"}
```

@prein / @michalroszka / @nandy-andy / @themech