dhcpd.conf not updated when user hits "Save cluster controller"

Steps to reproduce...

1) Setup a MAAS environment. In particular I have MaaS region controller (rc) and cluster controller (cc) in separate virtual machines.

2) Get the system to a point where you can enlist and allocate at least one machine.

3) Edit your Cluster controller and change its DNS name from the default master to something of your choosing, example

              master -> vm.maas

4) Hit the Save cluster controller

5) ssh to cluster controller and verify that /etc/maas/dhcpd.conf still shows 'master' as the domain nameserver.

Work around:

6) Go back to the Cluster Controller edit page.

7) click on edit "Interface" associated with the DHCP.

8) Click on 'Save interface' and see the blue info bar say Interface Saved.

9) Verify that /etc/maas/dhcpd.conf is now showing vm.maas.

Repercussions

10) Very bad behavior when deploying OpenStack.