A while ago, Docker split the "Domainname" field out from the "Hostname"
field for the container configuration. There was no real user-visible
change associated with this (and under the hood "Domainname" was mostly
left unused from the command-line point of view). We now add this flag
in order to match other proposed changes to allow for setting the NIS
domainname of a container.
This also includes a fix for the --hostname parsing tests (they would
not error out if only one of .Hostname and .Domainname were incorrectly
set -- which is not correct).
Signed-off-by: Aleksa Sarai <asarai@suse.de>
647579068f