* Remove the two hooks introduced in r52082

* Remove the two hooks introduced in r52082
* Remove the unused UserrightsChangeableGroups hook introduced in r39368 (1.14)
* Fix typo in Special:ListGroupRights introduced in r52083
* Prevent duplicate key display in Special:ListGroupRights (new behavior: if a permission is both assigned and revoked from a group, it only displays as revoked).
* Fix $wgRevokePermissions handling, it now runs after every group permission has been assigned in order to revoke the permission properly.