title: gtk FileChooserDialog: Allow only certain directory names
body: <p>I've seen <a href="https://stackoverflow.com/questions/10868167/make-filechooserdialog-allow-user-to-select-a-folder-directory">this question</a> that explains how to restrict a gtk FileChooserDialog so that only directories are allowed.</p>
  
  <p>I would like to place a further restriction so that only directories whose name match a certain pattern are allowed. I tried using a <code>gtk.FileFilter()</code> but it did not work:</p>
  
  <pre><code>self.logFileBrowseDialog = gtk.FileChooserDialog(title="Select Log Directory",
                         action=gtk.FILE_CHOOSER_ACTION_SAVE,
                         buttons=(gtk.STOCK_CANCEL,gtk.RESPONSE_CANCEL,
                                  gtk.STOCK_OPEN,gtk.RESPONSE_OK))
  
  self.logFileBrowseDialog.set_current_folder('/path/to/default/log/dir');
  logDirFilter = gtk.FileFilter()
  logDirFilter.set_name("Log Directory")
  logDirFilter.add_pattern("[0-1][0-9]-[0-3][0-9]-[0-9][0-9][0-9][0-9]-[0-2][0-9]-[0-5][0-9]-[0-5][0-9].[0-9][0-9][0-9]_GMT_Logs")
  self.logFileBrowseDialog.add_filter(logDirFilter)
  self.logFileBrowseDialog.set_action(gtk.FILE_CHOOSER_ACTION_SELECT_FOLDER)
  </code></pre>
  
  <p>Is it possible to only permit directories of a certain name? I realize that the user still needs a way to navigate away from an non-permitted directory to a permitted one. Ideally the "Open" button would be disabled if the current location does not meet the name criteria.</p>