Maintenance widget does not work on optimized build

The hashed mimeTypes.js file is not correctly being loaded.

![screen shot 2014-06-12 at 22 27 00](https://cloud.githubusercontent.com/assets/109850/3263918/5a8e60f2-f278-11e3-88b5-13bfa1992838.png)

As we can't really have these includes from within the current widget, can you revert the changes that were made in  #3766? Given this, I don't think they are applicable anymore.