Code review comment for ~mpontillo/maas:ha-dns-servers--bug-1753493

Ok, so I've quickly tested this, and it is dropping the IP of maas_url. I have this:

region/rack1: 90.1 & 90.2 (the latter is a "vip")
 - rackd.conf:maas_url: http://...90.1:5240/MAAS

region/rack2: 90.3
 - rackd:confmaas_url: http://...90.2:5240/MAAS

Before this change region/rackd2 have the following, which is missing 1 ip (90.3), but it is correctly using the value on rackd.conf:maas_url (which is the VIP 90.2)

ubuntu@node01:~$ cat /var/lib/maas/dhcpd.conf | grep domain-name-server
           option domain-name-servers 10.90.90.2, 10.90.90.1;
           option domain-name-servers 10.90.90.2, 10.90.90.1;

AFter this change it is correctly using the value of both *actual* regions, but it is dropping the VIP.

ubuntu@node01:~$ cat /var/lib/maas/dhcpd.conf | grep domain-name-server
           option domain-name-servers 10.90.90.1, 10.90.90.3;
           option domain-name-servers 10.90.90.1, 10.90.90.3;

This branch is regressing things even further.