Bug#682342: Latest patch successfully tested

[Nishanth Aravamudan <naravamudan@digitalocean.com>]

We are able to reproduce this issue at will in Ubuntu Bionic's installer
(not identical to Debian's, but code-wise in this path the same).
While quite a while after the last update from Philipp, we tested the
patch (netcfg_dhcp_domain.patch) after updating it to avoid a
compilation issue, we found it did fix the problem for us.

I am not sure if I can get Debian into our infrastructure to test
explicitly, but I will work on it; at the same time,  the code change
seems straightforward.

Thanks!
-Nish