remote: pass identity across to newly opened daemons

remote: pass identity across to newly opened daemons

When opening a connection to a second driver inside the daemon, we must
ensure the identity of the current user is passed across. This allows
the second daemon to perform access control checks against the real end
users, instead of against the libvirt daemon that's proxying across the
API calls.

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>