fix add-fixed-ip with quantum

bug 1157439

code was ignoring existing IPs on a port when adding a new IP.

Change-Id: I11f3c81eafc6c7d44772c3c8aea3b14f4b6bc815
Merge "fix add-fixed-ip with quantum"
Merge remote-tracking branch 'm_src_repo/master' into build-temp