Changed the cpanel icon to cogs

See:
http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=32326&start=0

Before:
![before](https://f.cloud.github.com/assets/906943/1339992/5a3c72c0-361b-11e3-998e-124d8f2b7b06.png)

After:
![after](https://f.cloud.github.com/assets/906943/1339991/5a3206b4-361b-11e3-8a8f-b8f3d88ac555.png)