fixing button float bug

Fixes a small bug on the commercial high relevance books component when the main book has no description.

Before;
![booksbroken](https://cloud.githubusercontent.com/assets/1303616/3218671/5ab2f0c6-efed-11e3-9943-6c78138b62eb.png)

After;
![screen shot 2014-06-09 at 16 47 36](https://cloud.githubusercontent.com/assets/1303616/3218677/688d9688-efed-11e3-908b-2b2d7554cd5d.png)