* Rename --ca-file to --os-cacert (--ca-file deprecated for
backward compatibility)
* Add cacert to keystoneclient initialization to verify the
keystone server certificate
This aligns glanceclient with keystoneclient for option naming
and the use of TLS for the keystone auth connection. It does not
change the use of TLS/SSL for the glance connection.
Change-Id: If8b05655aea5f3c62612d77bf947dd790f77eddf