[BusyBox] incorrect exit status for df, du, mount, umount

[Matt Kraai]

On Tue, Dec 05, 2000 at 11:39:43PM -0800, kent robotti wrote:
> I found these problems in the latest cvs bb.
> 
> df /doesn't_exist && echo yes
> df: can't find mount point
> yes
> 
> umount /doesn't_exist && echo yes
> yes
> 
> mount /dev/hda1 /doesn't_exist && echo yes
> mount: mount point does not exist
> yes
> 
> du doesn't_exist && echo yes
> du: no such file or directory
> yes

I just committed a patch which I believe fixes these problems.  It
worked in my tests, but I don't have root access at the moment so I
couldn't test all of the code paths.  Please test it and let me know if
find any problems.  The patch to du isn't perfect, but it needs to be
rewritten to use recursiveAction anyway.  I'll give it a shot if no one
beats me to it.

Matt