Remove extra padding on feed (bug 1068327)

https://bugzilla.mozilla.org/show_bug.cgi?id=1068327

![screenshot 2014-09-16 14 03 37](https://cloud.githubusercontent.com/assets/211578/4373899/29d7416e-4330-11e4-8a7d-d1f34645a3df.png)
Before


![screenshot 2014-09-23 09 48 18](https://cloud.githubusercontent.com/assets/211578/4373971/b24b3f78-4330-11e4-826f-19f008f5e11e.png)
After