See if we can specify L2 connectivity to networking-ansible

[tzumainn]

The ansible plugin is excluded when using ports that don't have a fixed IP, due to:

• https://opendev.org/openstack/neutron/src/branch/master/neutron/plugins/ml2/managers.py#L1062-L1073
• the ansible driver not specifying L2 connectivity

However it seems that this should be allowed, so perhaps we can update the ansible driver?

[tzumainn]

From testing, this PR will do the trick: https://github.com/CCI-MOC/networking-ansible/pull/1