Add PTR record for ns1.cacert.org in 2001:07b8:616.ip6 zone.
Drop dummy PTR record from 2001:07b8:616.ip6 zone.
Add AAAA record for ns1.cacert.org. to cacert.org zone.
Configure nsd for external access over IPv6.
Expand firewall script to support IPv6.
git-svn-id: http://svn.cacert.org/CAcert/SystemAdministration/ns/var/opendnssec/unsigned@2534 14b1bab8-4ef6-0310-b690-991c95c89dfd