ghanshyam b65b5bdfa2 Use ubuntu-xenial for openstack-tox-cover on stable
The openstack-tox-cover jobs using bionic nodetset on stable/rocky
and older stable branches.

This commit use xenial for stable branches previous to stein and
bionic for stein on.

Change-Id: Ica2d3de80da3ce467accc986d34f2b3c8ea79656
2019-03-26 20:02:39 +00:00
..