Fixed autoconf script to properly detect missing pkcs11 with polarssl.

Fixed autoconf script to properly detect missing pkcs11 with polarssl.

When polarssl is compiled without pkcs11 support, or a required
pkcs11-helper library is missing, configure will now issue an error.

Signed-off-by: Steffan Karger <steffan.karger@fox-it.com>
Acked-by: Adriaan de Jong <dejong@fox-it.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1363942465-3251-7-git-send-email-steffan.karger@fox-it.com>
URL: http://article.gmane.org/gmane.network.openvpn.devel/7441
Signed-off-by: Gert Doering <gert@greenie.muc.de>