busybox: inittab: don't redirect output to /dev/null

Several inittab steps are redirected to /dev/null. This means any error or
warning printed by these crucial commands would be hidden from the user.
There is no evident reason to hide this output, so stop doing that.

Suggested by Thomas Petazzoni:
http://lists.busybox.net/pipermail/buildroot/2015-September/139146.html



Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>