The pty field here is only present with certain tty types, so we shouldn't
unconditionally dereference it, or criu will hang.
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>