Rework of shutdown policy in inittab

This commit follows commit ad501b66. Start up of the busybox logging
daemons were moved to an init script but the shutdown were still
performed in inittab. This commit moves the shutdown policy to an
rcK script that calls the stop function of all the init scripts in
a reversed order.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>