Check qemu_chr_fe_set_msgfds() for errors, to make sure the message to
be sent is correct.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>