Embedded iframes no longer have border

Master:

![screen shot 2014-03-05 at 18 43 58](https://f.cloud.github.com/assets/109850/2336907/21cf1de0-a496-11e3-9303-907352c3d5f8.png)

Bootstrap3:

![screen shot 2014-03-05 at 18 44 45](https://f.cloud.github.com/assets/109850/2336914/42ce4fb6-a496-11e3-895e-c045506b9384.png)