Update the constraints url
Update the constraints url

For more detail, see http://lists.openstack.org/pipermail/openstack-discuss/2019-May/006478.html

Change-Id: I139ef3551f83b711c792ce54d3165c97318f802c

openstack/openstack-ansible-lxc_container_create,openstack/openstack-ansible-lxc_container_create