Page module serves cached search results

I tested this in two separate installations of PyroCMS 2.2/develop in the past few days. If you are [not in the `PYRO_DEVELOPMENT`environment](https://github.com/pyrocms/pyrocms/blob/2.3/develop/system/cms/modules/pages/controllers/pages.php#L78), the Pages module will serve cached page contents, even if you submit a search query via `$_GET`. That means, the first person who searches something gets fresh results, and everybody after that will get the first person's search results regardless of the search term …

Please note that I merely included the quick fix I deployed for a client, I'm not sure if it should be done that way …