dns: treating fully qualified and unqualified zone as identical.

dns: treating fully qualified and unqualified zone as identical.

"zone.com." and "zone.com" should be treated as the same zone.  This patch
picks the unqualified representation as standard and enforces it, in order to
match BIND9 behaviour.
Note: This fixes the failing test added previously, but that test still fails
on the rodc test target so we modify the expected failure but don't remove it.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13442
Signed-off-by: Aaron Haslett <aaronhaslett@catalyst.net.nz>
Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>