when shutting down, wrap the variable manipulation in splusb() so weird stuff doesn't happen if we're interrupted.
when shutting down, wrap the variable manipulation in splusb() so weird
stuff doesn't happen if we're interrupted.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars