Add a check for beta users in the video_info API

Discovered a case I missed on the original version of this. See
https://github.com/edx/edx-platform/pull/5798

@gwprice @ormsbee 

JIRA: MA-76
A convention I like to follow (per the pink-ice-cream django book) is to order the imports according to: 
(1) python core library modules
(2) external library modules
(3) edx-platform modules
(4) modules within this project.