when used with --testr=... the reload button causes a backtrace on the console

[Robert Collins]

Traceback (most recent call last):
  File "/home/robertc/source/tribunal/tribunal/window.py", line 201, in on_reload_button_clicked
    self.reload_from_source()
  File "/home/robertc/source/tribunal/tribunal/window.py", line 292, in reload_from_source
    self.load_from_subunit_stream(self.source.reload())
  File "/home/robertc/source/tribunal/tribunal/source.py", line 109, in reload
    res = cmd.execute()
  File "/usr/lib/python2.7/dist-packages/testrepository/commands/__init__.py", line 142, in execute
    self.ui.output_error(error_tuple)
  File "/home/robertc/source/tribunal/tribunal/trui.py", line 75, in output_error
    dialog = gtk.MessageDialog(self.window.subunit_window,
AttributeError: 'TestRepositorySource' object has no attribute 'subunit_window'