Code review comment for lp:~osomon/software-center/fix_appstore_update

Great catch, thanks a lot, Olivier! I made two small changes when merging, please take a look to make sure you see no problem with them:

 1. Also include a clear() for the app_index_map in the appstore's update() method.
 2. Drop the self.app_view.get_model().active = True in channelpane as that is always initialized when the new appstore is created.