Bug#288420: "Partition disks" fails without error if /target busy

[Christian Perrier <bubulle@debian.org>]

severity 288420 normal
merge 255050 288420
thanks

> This is indeed a known problem. libparted and thus partman doesn't like to
> modify the partition table while a partition is mounted, and thus fails to
> reread the partition table after partitioning, or plain refuses to do stuff.

Yes, this seems to be #255050

> 
> It is probable that a more meaningfull message should be showed here though.


Now that d-i is branched, there no objection for adding the message to
partman. NOT in sarge branch of course, because of the still standing
string freeze there.