Drop the xserver_unprotected interface.
    
    The motivation for this was xdm_t objects not getting cleaned up,
    so the user session tried to interact with them.  But since the
    default user type is unconfined this problem has gone away for now.
    
    Signed-off-by: Eamon Walsh <ewalsh@tycho.nsa.gov>
    Signed-off-by: Chris PeBenito <cpebenito@tresys.com>