s4-dns: dlz_bind9: Fix ipv6 updates

s4-dns: dlz_bind9: Fix ipv6 updates

b9_record_match needs to consider all allowed representations of IPv6
addresses (RFC 2373), otherwise DNS subtractrdataset operations fail
due to differences in zero padding between bind9 frontend and ndr_pull
of a dnsp_DnssrvRpcRecord structure.

Change-Id: Ic0a1b16008458993dc644646d7f4ae3d3a3c5fed
Signed-off-by: Arvid Requate <requate@univention.de>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Kai Blin <kai@samba.org>
Reviewed-by: Guenter Kukkukk <kukks@samba.org>