tty: Restore peers uid, gid

Currently when we create peers we don't consider
if they were owned by someone else. Lest carry
uid/gid into image and restore then.

https://github.com/xemul/criu/issues/198



Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>