Allow to parametrize the hardcoded 'undercloud' domain name.
F.e. RDOcloud uses an 'rdocloud' domain, therefore some DNS things might be
failing with the hardcoded value.
The default domain name remains unchanged. It can be
overriden with a new '--local-domain' option as well.
Related-bug: #1698349
Partial-bug: #1733873
Change-Id: Iad63142b241f9f7f0bbef68473f18b69f36daf76
Signed-off-by: Bogdan Dobrelya <bdobreli@redhat.com>
909a9f7530