[Toybox] Fix paths to avoid confusing update-alternatives

[Isaac Dunham]

Looking over landley.net/hg/toybox, I noticed this commit:
changeset 1775:57f2a26fa92c
 To ensure that toybox can be installed alongside busybox without 
 confusing update-alternatives, the paths of the links installed by
 toybox should match those installed by busybox. This is accomplished
 by changing the flags of a few tools within toybox.

Most of these are correct, but a few are the result of busybox being
plainly wrong:
readlink, df, and cut all belong in /bin (as per `which` on Debian).

df should certainly not be installed in /usr/sbin, since it is a user
tool rather than a purely administrative one; cut is frequently used
in boot scripts, which means it should go in the prefix "/", rather 
than "/usr"; and /etc/init.d/udev uses readlink specifically because
it's in /bin rather than /usr/bin.

These should be fixed in busybox.

I'll send a patch to fix them in toybox once the git mirror updates.

Thanks,
Isaac Dunham