Fix samba_dlz when named "reloads".

[github at samba.org]

New comment by abartlet on Samba Github repository

https://github.com/samba-team/samba/pull/124#issuecomment-449078220
Comment:
> However, I'm curious as to why the pull request wasn't just accepted. I got no comment whatsoever, but it clearly fixed the issue. See the explanation above.

We are well aware of a number of patches meant to address this issue.  However as we could not reproduce the issue (significant time was spent), and because bind9 is not part of our automated test system, we can't just apply patches and hope. 

What we did do is write tests that try to emulate every possible bad behaviour BIND9 could force on our plugin, to ensure we are robust to that.  That is 8c754b4396d958cb153c792615769efb00ed4bbd.

We are moving away from GitHub to GitLab, so bugzilla is probably the best place to continue the conversation with any backtraces, and GitLab is the place to test out further patches.  I've CC'ed Aaron who did the testing and logging work there and so I'll close this ticket for now.