Deprecate --ns-cert-type

Deprecate --ns-cert-type

The nsCertType x509 extension is very old, and barely used.  We already
have had an alternative for a long time: --remote-cert-tls uses the far
more common keyUsage and extendedKeyUsage extensions instead.

OpenSSL 1.1 longer exposes an API to (separately) check the nsCertType x509
extension.  Since we want be able to migrate to OpenSSL 1.1, we should
deprecate this option immediately.

Signed-off-by: Steffan Karger <steffan@karger.me>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1488653397-2309-1-git-send-email-steffan@karger.me>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg14222.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>