Print client id only if compiled with man agent support. Otherwise
print an empty string.

Also use %lu instead of %u for printing unsigned long int

Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1365687278-3921-1-git-send-email-arne@rfc2549.org>
URL: http://article.gmane.org/gmane.network.openvpn.devel/7498

Signed-off-by: Gert Doering <gert@greenie.muc.de>