Override Mesos config in configuration tests
Override Mesos config in configuration tests

To ensure that the requests_mock will work everywhere, we have
to override the host setting.

TrivialFix

Change-Id: Ia4c51c913b03f6926f83c8cb5616bb1e757fcd37

openstack/kolla-mesos,openstack/kolla-mesos,asalkeld/kolla-mesos,openstack/kolla-mesos