[sudo-workers] nscd does not handle "(none)" string

[Todd C. Miller]

On Tue, 13 Sep 2016 08:02:17 -0400, Tomas Sykora wrote:

> By default, when no domainname is set, the string "(none)" is returned by get
> domainname.
> nscd does not handle the "(none)" string, it's really using it to search for 
> entries in its cache.
> This domainname value is then used as the domain parameter in the triple (hos
> t,user,domain).

I may be missing something but it looks like the existing code
already does this.  If getdomainname() does not fail and it contains
an illegal character, domain is freed and set to NULL.

It does look like there is a bug when getdomainname() fails though.
I've committed a fix for that in:
    https://www.sudo.ws/repos/sudo/rev/946f2441c90a

 - todd