codfw row B labs network

Allocate a /24 for labs support hosts on codfw row B. Leave:

10.192.4.0/24
10.192.20.0/24
10.192.36.0/24
10.192.52.0/24

for labs hosts free for now.

Accordingly other rows should have:

10.192.5.0/24
10.192.37.0/24
10.192.53.0/24

Change-Id: Ie7046404bd7152d5c678a5bdc15fe9a63b6db669