Zero initialise msghdr prior to calling sendmesg

Zero initialise msghdr prior to calling sendmesg

This ensure that all unused fields in msg are zero.

Spotted by Coverity:

Using uninitialized value "msg". Field "msg.msg_flags" is uninitialized
when calling "sendmsg".

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Antonio Quartulli <antonio@openvpn.net>
Message-Id: <20210105131758.20311-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg21418.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>