Bug fix for 1352460, Check gateway part of subnet cidr in network update, before creating subnet.
https://bugs.launchpad.net/juniperopenstack/+bug/1352460

Change-Id: Ibe55d18f3990e1cfd13915af9812c91d2cb96544
Merge "Bug fix for 1352460, Check gateway part of subnet cidr in network update, before creating subnet. https://bugs.launchpad.net/juniperopenstack/+bug/1352460" into R1.10