[Cooker] Can't edit items on gnome desktop

[Bellegarde C�dric]

Since gnome-2.2, we can't edit items on gnome-desktop. The function
always exist  ("editer le lanceur" in french) but only in
applications:///. gnome-2.4 will be out soon and function is always
unavailable. It will be cool to add a little patch to add an item in
gnome-desktop/nautilus menu :)