do not include --cipher value in data-ciphers

do not include --cipher value in data-ciphers

The --cipher option has been there since a while, but it became more and
more confusing since the introduction of NCP (data cipher negotiation).

The fallback cipher can now be specified via --data-cipher-fallback,
while the list of accepted ciphers is specified via --data-ciphers.

--cipher can still be used for compatibility reasons, but won't affect
the cipher negotiation.

Adjust manpage to make clear that using --cipher in today's config really
is a thing from the past, and --data-ciphers should be used instead.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <20210904095629.6273-5-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg22799.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>