Comment 16 for bug 1663757

Let's fix this bug in the following way:

pick-up patch [1] which adds a new field in the cluster template and CHANGE it.

Instead of adding a new field we should add a configuration parameter in
magnum.conf and pass it to the heat-templates similarly to patch [1].

Create a new fine in [2] named drivers and add a configuration parameter there,
named verify_ca which will default to True.

[1] https://review.openstack.org/#/c/447687
[2] http://git.openstack.org/cgit/openstack/magnum/tree/magnum/conf