add support for neutron/nova notifications

This adds options to configure the Neutron -> Nova notifications of port
status and data changes.  Requires puppet-neutron module with the
appropriate support (e.g., https://review.openstack.org/#/c/87005/).

Change-Id: I26684a8fe5df79db6b68a5bd733619517376660c
Closes-bug: 1306337
initial live migration support

Change-Id: I38c2aee3a7415bb69a099419f6149151c7d6b52c