broken links causing assert/abort

[Noel Power]

whilst trying to test some export stuff I was suffering from libreoffice 
bailing out due to an assert. Problem is in the mysterious UCP layer :-) 
If you have a broken link in a directory the ucp sniffs then the abort 
occurs ( e.g. in my case for some reason I had the libreoffice file 
selector enabled and had such a broken link in my home dir )

A tentative fix is here

http://cgit.freedesktop.org/libreoffice/core/commit/?id=45b57a9dfb5df8b9c4a1974cb6e848d4f3b57ea3&ignorews=1

seems in the past we were forgiving with such a broken link and returned 
a blank string when trying to get a url. Saying that registering for 
notifications, setting & inserting ucb properties for such a 
non-existing file doesn't seem correct. I think that the FileBase stuff 
is correct to assert and that the patch for the client code to avoid 
using a broken file is not a crazy solution. cc'ing you here Stephan as 
I think you know much about this sorta stuff

Noel