$ sudo update-manager --dist-upgrade
ERROR:root:not handled expection:
Traceback (most recent call last):

  File "/usr/bin/update-manager", line 100, in <module>
    controler.doPartialUpgrade()

  File "/usr/lib/python2.6/dist-packages/DistUpgrade/DistUpgradeController.py", line 1595, in doPartialUpgrade
    if not self.doDistUpgrade():

  File "/usr/lib/python2.6/dist-packages/DistUpgrade/DistUpgradeController.py", line 972, in doDistUpgrade
    self.quirks.run("StartUpgrade")

  File "/usr/lib/python2.6/dist-packages/DistUpgrade/DistUpgradeQuirks.py", line 77, in run
    for plugin in self.plugin_manager.get_plugins(condition):

  File "/usr/lib/python2.6/dist-packages/computerjanitor/plugin.py", line 167, in get_plugins
    filenames = self.get_plugin_files()

  File "/usr/lib/python2.6/dist-packages/computerjanitor/plugin.py", line 120, in get_plugin_files
    basenames = [x for x in os.listdir(dirname)

OSError: [Errno 2] No such file or directory: './plugins'

ERROR:root:failed to import apport python module, can't report bug: No module named python_hook
none