Conflict with older gnome-shell versions
    
    Added expicit Conflicts with gnome-shell < 3.7.90 to ensure both
    gnome-shell and gnome-desktop3 get updated in lockstep. We don't have
    new gnome-shell in rawhide yet and the gnome-desktop3 3.7.90 update
    would break older gnome-shell versions because of the GnomeIdleMonitor
    API change.