Remove --client-cert-not-required

Remove --client-cert-not-required

This removes support for the --client-cert-not-required option.  To
avoid starting a server with this option just ignored, which would make
it impossible for existing clients to connect it will exit with
instructions to replace this option with --verify-client-cert none.

Signed-off-by: David Sommerseth <davids@openvpn.net>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20200720113010.10450-1-davids@openvpn.net>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg20502.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>