df command should suppress duplicates

[Ondrej Oprala]

Hi,
 I've written a little fix for this bugzilla 
https://bugzilla.redhat.com/show_bug.cgi?id=709351
which I think could solve the duplicity output problem. The idea is that 
df would keep a linked
list of device numbers it already went through and not count in 
(get_dev) those filesystems again
when running into them as bind mounts.
Cheers,
 Ondrej.

DIFF
Description: Text document