[Bug 82397] Use a more sensible message for "unknown" in permission tab.

[joelbryan]

Public bug reported:

Binary package hint: nautilus

The term "unknown" in permission tab in nautilus file-manager is
misleading, since people might think that it is related to fam/gamin
issues, but it is not.

A message that says "No user permissions had been defined" is logical
and much more helpful.

** Affects: nautilus (Ubuntu)
     Importance: Undecided
         Status: Unconfirmed

-- 
Use a more sensible message for "unknown" in permission tab.
https://launchpad.net/bugs/82397