qemu_socketpair() will create a pair of connected sockets
with FD_CLOEXEC set

Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn>
Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <17fa1eff729eeabd9a001f4639abccb127ceec81.1661240709.git.tugy@chinatelecom.cn>