Move tripleo-bm-test network to 172.16.0.0/22

We now have enough capacity in one rack to exceed 192.168.1.0/24 so
we agreed at the mid-cycle to scale this up to 172.16.0.0/22 -
allowing room for other uses in the same ip space, but exceeding our
current capacity by a comfortable margin.

Change-Id: I0aa99ec063d9c855e7e49416f0840d3b58a5e202
Co-Authored-By: Derek Higgins <derekh@redhat.com>
Merge "Move tripleo-bm-test network to 172.16.0.0/22"