Fix description of --client-disconnect calling convention in manpage.

Fix description of --client-disconnect calling convention in manpage.

The man page claimed that --client-disconnect "is passed the same
pathname as the corresponding --client-connect command", which is
not what the code does.  Fix.

Reported-By: hvenev in Trac
Trac: #884

Signed-off-by: Gert Doering <gert@greenie.muc.de>
Acked-by: Antonio Quartulli <a@unstable.cc>
Message-Id: <20200909122926.9523-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg20929.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit 50c7700da09a1f83474e18f8709d59dbc4b509e2)