Log SSL alerts more prominently

Log SSL alerts more prominently

When we receive an SSL alert from a server we currently only log a
very cryptic OpenSSL error message:

   OpenSSL: error:0A00042E:SSL routines::tlsv1 alert protocol version:SSL alert number 70

This also enables logging the much more readable SSL error message:

   Received fatal SSL alert: protocol version

which previously needed --verb 8 to be displayed (now verb 3). Also rework the
message to be better readable.

Change-Id: I6bdab3028c9bd679c31d4177a746a3ea505dcbbf
Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Frank Lichtenheld <frank@lichtenheld.com>
Message-Id: <20231121103930.15175-1-frank@lichtenheld.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg27523.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>