Use templates for cover and lower-constraints
Use templates for cover and lower-constraints

Use openstack-tox-cover template, this runs the cover job
in the check queue only.

Use openstack-lower-constraints-jobs template

Remove jobs that are part of the templates.

Change-Id: Id210b2f15dcba9dcf9ad75e0436995e7d5c1b62b

openstack/python-openstackclient,openstack/python-openstackclient,dtroyer/python-openstackclient,dtroyer/python-openstackclient