Fixes #165. Don't apply iOS7 font style to iOS6 publish/update button.

Before: 

![screen shot 2013-11-08 at 1 27 15 pm](https://f.cloud.github.com/assets/1435271/1503496/d3d7f530-48ab-11e3-893f-fd1a037de5a4.png)


After: 

![screen shot 2013-11-08 at 1 12 37 pm](https://f.cloud.github.com/assets/1435271/1503468/8245f4e2-48ab-11e3-94a1-c2440d8e4a7a.png)