Fix shutdown, reboot, halt, poweroff

[nezticle]

These commands don't actually do what they are supposed to. Pulling the power plug are random times seems to have negative results on the integrity of my ext4 file-system.

[Tibalt]

not fix yet? I have found the same problem in the latest version.

Probably not fixed yet, but I haven't seen corrupted filesystems when I use 'reboot -f'
All rpi instances using ext4 for filesystems