cloud-compute-relation-changed fails when short hostname is not resolvable

[José Pekkarinen]

Since openstack train I noticed new deployments produce the
charm to follow a path of nova_cc_utils to check the short
hostname using a ns lookup query. Even when the host is configured
to lookup the domains configured in openstack, in the end the
query fails and leave the charm in error state.

From systemd-resolve --status:

          DNS Domain: dev.mydomain.com
                      adm.mydomain.com
                      int.mydomain.com

The domain is registered in maas, and the record is available,
as if I query the hostname, I get:

$ dig +short os-ha-1.dev.mydomain.com
10.10.10.32
$ dig +short os-ha-1
$

Removing the lines that issues the query makes the code continue
the deployment of nova-cc without noticeable issue.

A patch to remove the lines will be proposed.

José.