Fix feedback button styling

Before:

![2014-11-10 at 09 40](https://cloud.githubusercontent.com/assets/296432/4973857/3b5d4baa-68be-11e4-9219-ad91e95c5e4c.png)

After:

![2014-11-10 at 09 45](https://cloud.githubusercontent.com/assets/296432/4973871/54657424-68be-11e4-8ff3-3aa53fee869d.png)