fixed gnome-utils non translatable strings

[Sebastien Bacher]

Hello there,

I've fixed http://bugzilla.gnome.org/show_bug.cgi?id=523524 and marked
"Could not detect any mount point." and "Without mount points disk usage
cannot be analyzed." translatables in the gnome-utils hardy packages,
the change has also been commited upstream in trunk so those might be
translated upstream for GNOME 2.22.1 too.

Sebastien Bacher