Fix navigation bottom row size when there is no current site/beta switch

### Before

![screen shot 2014-07-28 at 11 25 44](https://cloud.githubusercontent.com/assets/85783/3719336/e3bf2798-1641-11e4-94bd-502cf9e0a944.PNG)


### After

![screen shot 2014-07-28 at 11 25 30](https://cloud.githubusercontent.com/assets/85783/3719338/e6911486-1641-11e4-96ab-ba325a0733c9.PNG)

![ ](http://gifs.joelglovier.com/ohhh/ohhh-minion.gif)