gate-grenade-dsvm-neutron-multinode-live-migration-nv failing on stable/newton due to devstack not supporting xenial during Mitaka

[Lee Yarwood]

Description
===========
gate-grenade-dsvm-neutron-multinode-live-migration-nv failing on stable/newton due to devstack not supporting xenial during Mitaka.

Steps to reproduce
==================
Attempt to run gate-grenade-dsvm-neutron-multinode-live-migration-nv against stable/newton.

Expected result
===============
gate-grenade-dsvm-neutron-multinode-live-migration-nv is able to install devstack using stable/mitaka on xenial.

Actual result
=============
gate-grenade-dsvm-neutron-multinode-live-migration-nv currently fails to install devstack using stable/mitaka as xenial is not listed as a tested release.

Environment
===========
Any stable/newton xenial based grenade job.

Logs & Configs
==============
http://logs.openstack.org/08/404508/3/check/gate-grenade-dsvm-neutron-multinode-live-migration-nv/36898db/logs/grenade.sh.txt.gz#_2016-11-30_09_23_03_218

[Matt Riedemann (mriedem)]

https://review.openstack.org/#/c/404803/