'Patches a plugin model by forcing a specifc db_table whether the
\'new style\' table name exists or not. The same goes for all the
ManyToMany attributes.
This method must be run whenever a plugin model is accessed
directly.
The model is modified in place; a \'patched\' attribute is added
to the model to check whether it\'s already been modified.'

def set_plugin_meta(self):

    if self.patched:
        return
    self.patched = True
