Cinder client does not honor disable_ssl_certificate_validation

The Client() class should pass in insecure as the value of
CONF.identity.disable_ssl_certificate_validation, otherwise many
tests will fail if the cinder server is secured with SSL.

Change-Id: I9bb6ff48a0d53b5b124e58c9959c9a43da8c7e5c
Closes-Bug: 1298019
Merge "Cinder client does not honor disable_ssl_certificate_validation"