Replaced orphan "What's This" button with two individual tooltips for... 

..."Visibility" and "Share With" help on the Upload file page.

The following two screenshots show the new layout:

![whats_this_is_gone](https://cloud.githubusercontent.com/assets/568286/3554259/5e2a16c6-090b-11e4-9683-c9e6bfab575b.png)

![help_text](https://cloud.githubusercontent.com/assets/568286/3554260/60c7697e-090b-11e4-9124-cf0e868ce824.png)