File chooser can't select files if some file changes

[Federico Mena Quintero <federico ximian com>]

Hi, everyone,

Some distros are shipping GTK+ 2.20.x.  This branch didn't get this
important fix:

https://bugzilla.gnome.org/show_bug.cgi?id=623343

That only appeared in 2.22 and later.  If you get bugs along the lines
of this:

	- open a file chooser
	- click on a file
	- make some file in the same folder get changed (e.g. touch it)
	- click on another file - nothing happens

Then you'll want the patch from that bug :)

This has been a public service brown paper bag.

  Federico