Fix local-unbound setup for some IPv6 deployments.

PR:		250984
MFC after:	1 week

usr.sbin/unbound/setup/local-unbound-setup.sh

@@ -66,7 +66,7 @@ bkext=$(date "+%Y%m%d.%H%M%S")
 RE_octet="([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])"
 RE_ipv4="(${RE_octet}(\\.${RE_octet}){3})"
 RE_word="([0-9A-Fa-f]{1,4})"
-RE_ipv6="((${RE_word}:){1,}(:|(:${RE_word})*)|::1)"
+RE_ipv6="((${RE_word}:){1,}(:|${RE_word}?(:${RE_word})*)|::1)"
 RE_port="([1-9][0-9]{0,3}|[1-5][0-9]{4,4}|6([0-4][0-9]{3}|5([0-4][0-9]{2}|5([0-2][0-9]|3[0-5]))))"
 RE_dnsname="([0-9A-Za-z-]{1,}(\\.[0-9A-Za-z-]{1,})*\\.?)"
 RE_forward_addr="((${RE_ipv4}|${RE_ipv6})(@${RE_port})?)"