don't print errno twice

don't print errno twice

when passing the M_ERRNO flag to msg(), the latter will already
print the errno message (in a form of a string and number) for us,
hence there is no need to explicitly print it a second time.

Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <20170713080527.13299-2-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15057.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit e441d861881669c97906652c3278cc9a6c69a417)