botoclient does not honor disable_ssl_certificate_validation

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

Change-Id: Id4759645ca84fd0fd7e41d2ffe72c6ae36d3b604
Closes-Bug: 1307675
Merge "botoclient does not honor disable_ssl_certificate_validation"