Revert "Bug 930104 - Remove localId=0 hack for the system app on firefox and correctly set permission for any app loaded in Firefox r=vingtetun"

This reverts commit 73840d5463c15cf7bb535eda813b666b933fa11a.
Merge pull request #13299 from mikehenrty/master

Revert "Bug 930104 - Remove localId=0 hack for the system app on firefox...