Fixed Bug985004 -- Add admin ability to make locatio inactive

added is_active in location table. Did south migration.

https://bugzilla.mozilla.org/show_bug.cgi?id=985004#c3

New `is active?` checkbox is here: 
![is_active](https://cloud.githubusercontent.com/assets/954858/2597861/6f3d46c0-babb-11e3-94b0-10aad23f4cbb.png)