[CFT] Remove NIS

Eh ...

No, I am not planning to remove NIS, au contraire, but now
that I got your attention ...

We have a couple of long standing (2001) NIS-related issues
with patches and I am willing to do something about it.
Please test:

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=26486
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=31981

Thanks in advance,

Pedro.