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

Mike I have some inline comments, but also I have a few questions.

Say we have this:

1. Scenario 1:
region/rack1 - 10.1
region/rack2 - 10.2

This would yield DNS such as 10.1, 10.2

2. Scenario 2:
region/rack1 - 10.1 | foalting IP on same subnet 10.3
region/rack2 - 10.2

This would yield to DNS be 10.3, 10.1, 10.2

3. Scenario 3 (isolated region/rack networks):
region/rack1 - 9.1
region/rack2 - 9.2
rackd.conf:maas_url in both points to: 10.1 and they have a proxy in the rack.

This would yield to DNS be 10.1 and not (9.1 nor 9.2). This should be the same for deployed machines.