command to refresh iarc ratings for apps (bug 981100)

[cage-fighter](http://marketplace.firefox.com/app/cage-fighter) has some missing descriptors, interactive elements, and some incorrect ratings. Somehow our db got out of sync with their certs, possibly due to a bug that has since been fixed (cage-fighter attained ratings in late January).

This adds a command to resync with IARC certs. @robhudson