Comment 2 for bug 747679

Starting Bauble from command line fails with:

Traceback (most recent call last):
  File "/usr/bin/bauble", line 28, in <module>
    bauble.main()
  File "/usr/share/bauble/__init__.py", line 175, in main
    import bauble.pluginmgr as pluginmgr
  File "/usr/share/bauble/pluginmgr.py", line 315, in <module>
    class PluginRegistry(db.Base):
  File "/usr/share/bauble/db.py", line 58, in __init__
    super(MapperBase, cls).__init__(classname, bases, dict_)
  File "/usr/lib/python2.6/dist-packages/sqlalchemy/ext/declarative.py", line 1017, in __init__
    _as_declarative(cls, classname, cls.__dict__)
  File "/usr/lib/python2.6/dist-packages/sqlalchemy/ext/declarative.py", line 1010, in _as_declarative
    **mapper_args)
  File "/usr/lib/python2.6/dist-packages/sqlalchemy/orm/__init__.py", line 818, in mapper
    return Mapper(class_, local_table, *args, **params)
  File "/usr/lib/python2.6/dist-packages/sqlalchemy/orm/mapper.py", line 211, in __init__
    self._configure_pks()
  File "/usr/lib/python2.6/dist-packages/sqlalchemy/orm/mapper.py", line 490, in _configure_pks
    (self, self.mapped_table.description))
sqlalchemy.exc.ArgumentError: Mapper Mapper|PluginRegistry|plugin could not assemble any primary key columns for mapped table 'plugin'

Regards