Remove DES check with OpenSSL 3.0

Remove DES check with OpenSSL 3.0

DES is very deprecated and accidently getting on the of the 16 insecure
keys that OpenSSL checks is extremely unlikely so we no longer use the
deprecated functions without replacement in OpenSSL 3.0.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20211019183127.614175-5-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg23004.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>