BAC-1301: Don't purge history page as they're not cached on Varnish

Purges of history page are more than 20% of all purge requests in our queue. Remove them as they're not cached on Varnish:

```
$ curl -I "http://poznan.wikia.com/wiki/W%C4%85tek:25212?action=history" -s | grep -i "Cache-Control"
X-Cacheable: NO:Cache-Control=private
Cache-Control: private, s-maxage=0, max-age=0, must-revalidate
```

@michalroszka / @prein