polarssl: fix --client-cert-not-required

polarssl: fix --client-cert-not-required

PolarSSL 1.3 determines whether to use a client key/cert based on the
private key and/or certificate structs being allocated or not.  We
previously would always allocate the structs in
tls_ctx_{client,server}_new(), which made polarssl clients without a
client key/cert (can also be mgmt-external-key or pkcs11) fail to connect.

Note that this bug is not present in OpenVPN 2.3, because PolarSSL 1.2
does not contain the 'pk' abtraction layer and therefore behaves slightly
different.

Signed-off-by: Steffan Karger <steffan@karger.me>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <1444948995-18720-2-git-send-email-steffan@karger.me>
URL: http://article.gmane.org/gmane.network.openvpn.devel/10287
Signed-off-by: Gert Doering <gert@greenie.muc.de>