added INSISTs to verify that zone timer intervals are set before use
added INSISTs to verify that zone timer intervals
are set before use

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