Fix floating in pull request listing

At the moment, the PR listing looks a bit awkward:

![](https://cloud.githubusercontent.com/assets/153481/5243207/673b8488-7941-11e4-80bc-3425bf53261b.png)

This is fixed by this PR:

![](https://cloud.githubusercontent.com/assets/153481/5243213/84b81166-7941-11e4-9929-2bfdeba3e1bf.png)