Revision 372200

- Update to 1.6.0
  * Add persistent timers for slave zones (expire, refresh, and flush)
  * Return minimal response for queries with unsupported EDNS version
  * Fix DNSSEC compliant processing of letter case in RDATA domain names
  * Fix interpretation of Extended RCODE in EDNS
  * Fix forced zone retransfer on slave
  * Fix zone expiration when transfer is being refused by master

PR:	194795
Submitted by:	freebsd@dns-lab.com (maintainer)