Fix bind DLZ module to prevent zone transfers for everyone

[github at samba.org]

New comment by abartlet on Samba Github repository

https://github.com/samba-team/samba/pull/213#issuecomment-447760310
Comment:
@littlejawa could you re-open this over at GitLab per https://wiki.samba.org/index.php/Samba_CI_on_gitlab

I know you started here before we put up the notices, but we are trying to shut down our GitHub activity and move to GitLab as the web development portal for the Samba Team (along with samba-technical of course).

However I can say one thing, it will need tests.  There is an smbtorture test harness for this already, so that should be extended. 

Thanks!