Updated openstack/openstack
Project: openstack/neutron  1f578d2572490e755179c3d4a351be1049091bfa

Apic drivers enhancements (second approach): L2 refactor

- refactor to leverage Client's transactional capabilities
- General refactor to improve the driver's reliability

Implements blueprint: apic-driver-enhancements

Change-Id: I4deb171381e62e70818218957d82b5e27954aeb9