When deploy openstack with selfsigned CA cert, the senlin-dashboard unable to fetch required data.
Adding `cacert = settings.OPENSTACK_SSL_CACERT` and `insecure = settings.OPENSTACK_SSL_NO_VERIFY` to build ks_session.Session suitable for current environment and fix SSL Error issue
Closes-Bug: #2047622
Change-Id: I949871801d147a14b53696d3ebad79f0b4c8d3a7