The 'show' action has been deprecated since 1.6, let's finally drop it.

The print_data() routine is kept for yet another (to be deprecated too)
feature called 'criu exec'.
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>