Change firewall to DOWN when admin state down

Currently firewall remains in status "ACTIVE" after admin state
is changed to DOWN.

This fix sets firewall status to "DOWN" if admin state is updated
from "UP" to "DOWN". "DOWN" status is used by other network resources
so use "DOWN" to keep consistent.

Change-Id: If316b114c4df78368b43c2a15a820bb1177b3a54
Closes-Bug: 1279213
Merge "Change firewall to DOWN when admin state down"