Prevent pull request float fail when no body

# Before 
![screen shot 2014-12-01 at 10 10 17](https://cloud.githubusercontent.com/assets/803765/5243316/e21caea6-7942-11e4-8ecd-6947e7be21a2.png)

# After
![screen shot 2014-12-01 at 10 13 33](https://cloud.githubusercontent.com/assets/803765/5243320/e9efeb5c-7942-11e4-8105-0028aa416a7d.png)