Decrement carp_suppress_preempt when detaching an interface that has been experiencing output errors.
Decrement carp_suppress_preempt when detaching an interface that has
been experiencing output errors.

ok mcbride@

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