msg notifiying devs app will be disabled on 4/15 if no ratings (bug 950245)

![screen shot 2013-12-13 at 4 16 04 pm](https://f.cloud.github.com/assets/674727/1747256/f205916a-6454-11e3-990f-9baac0327c58.png)

Also partly done in https://github.com/mozilla/zamboni/pull/1534