Port the fix for nova floatingip issues and quota driver import error

Two issues are fixed
1. Fix the nova floating-ip-* issues. Ported the code from the below pull requests from sbansal7
   https://github.com/Juniper/contrail-neutron-plugin/pull/34/files
   https://github.com/Juniper/contrail-neutron-plugin/pull/35/
   https://github.com/Juniper/contrail-neutron-plugin/pull/20
2. Fix the quota driver import error