Neutron ML2 plugin introduces the first extension driver port_security, this
patch add it to be a default extension driver as a example. And also, if not
set it by default, networks like public/private which are created after the
neutron-db-manage's update, will not include the port-sec value.
Change-Id: I3035317c83d22804855517434bd8578719ce0436
Partially Implements: blueprint ml2-ovs-portsecurity
a48e5dc4bd