zone_settimer should do nothing if the zone is exiting.  Previously, some of the callers checked this, but not all of them.
zone_settimer should do nothing if the zone is exiting.  Previously, some of
the callers checked this, but not all of them.

pecharmin/bind9,each/bind9-collab,each/bind9-collab,each/bind9-collab,pecharmin/bind9,pecharmin/bind9,each/bind9-collab,pecharmin/bind9,each/bind9-collab,pecharmin/bind9,pecharmin/bind9,each/bind9-collab