Allow trailing \r and \n in control channel message

Allow trailing \r and \n in control channel message

Writing a reason from a script will easily end up adding extra \r\n characters
at the end of the reason. Our current code pushes this to the peer. So be more
liberal in accepting these message.

Github: closes OpenVPN/openvpn#568

This is the backport of the fix (commit be31325e1dfdffb) to release/2.5.

Change-Id: I47c992b6b73b1475cbff8a28f720cf50dc1fbe3e
Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20240711113022.52076-1-frank@lichtenheld.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg28923.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>