free_ip does not take subnet argument any more
free_ip does not take subnet argument any more

Also fixed some flake8 issues

Change-Id: I56e8cc163997a70e6388032a89735151a6b80ce4
Closes-Bug: 1658757

eonpatapon/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,rombie/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,nischalsheth/contrail-controller,rombie/contrail-controller,eonpatapon/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller,nischalsheth/contrail-controller,eonpatapon/contrail-controller,nischalsheth/contrail-controller