Enable or disable fence

def set_fence_enabled(self, do_enable):
        '''Enable or disable fence'''
        self.master.mav.command_long_send(
            self.target_system,
            self.target_component,
            mavutil.mavlink.MAV_CMD_DO_FENCE_ENABLE, 0,
            do_enable, 0, 0, 0, 0, 0, 0)