Config parsing: Ignore some BIND9-specific resolv.conf options

[adns] / regress / init-unkopts.text

nameserver 172.18.45.6
sortlist 127.0.0.1/32 172.18.45.0/28 172.18.45.0/24
search davenant.greenend.org.uk greenend.org.uk
lwserver 127.0.0.1
options timeout:1 attempts:30 rotate no-check-names inet6 edns0 wombat
stoat