Changes to remove the use of mapping tables from Nuage plugin

Nuage plugin maintains a mapping of Openstack and Nuage resources.
With this change Nuage VSD can itself maintain this mapping, so the
plugin doesn't have to store the information in the neutron DB.
This eliminates potential out of sync and upgrade issues.

Closes-Bug: #1338853

Change-Id: I03b32a83d792c742962e0195383a622c1967ae4f
ML2 additions to support DVR

This patch introduces the changes necessary to
support DVR at Layer 2 with ML2, and L2pop.

Partially-implements: blueprint neutron-ovs-dvr

Change-Id: I709d877e7df83728868e68e023e6a37bb2e11704
Authored-by: Vivekanandan Narasimhan <vivekanandan.narasimhan@hp.com>
Updated from global requirements

Change-Id: I4116476698feba5b17ed4443db75a27c53da8615
Merge "Changes to remove the use of mapping tables from Nuage plugin"
Merge "Updated from global requirements"
Merge "ML2 additions to support DVR"