Keep federation jobs running on Xenial
Keep federation jobs running on Xenial

Devstack/Tempest are going to migrate to the latest Ubuntu LTS release
18.04 aka Bionic, but there is an issue with the apache shibboleth
module, see [1] and [2].

As a workaround we keep the federation jobs running on Xenial for now.

[0] https://etherpad.openstack.org/p/devstack-bionic
[1] https://bugs.launchpad.net/keystone/+bug/1802901
[2] https://bugs.launchpad.net/ubuntu/+source/xmltooling/+bug/1776489

Change-Id: I8ad93577b1e5a5084e2a65cb1377eb7b0d353cb7
Depends-On: https://review.openstack.org/620906

mahak/keystone,openstack/keystone,openstack/keystone,mahak/keystone,openstack/keystone,mahak/keystone