Odoo 6.0 upgrade_openerp issue

[petrus-v]

I get the following message when I use the generated upgrade_openerp script using openerp 6.0 with this following config:

[buildout]
parts = openerp
versions = versions
find-links = http://download.gna.org/pychart/


[openerp]
recipe = anybox.recipe.openerp[bzr]:server
version = git https://github.com/Odoo/odoo.git odoo 6.0
...

Error:

/home/pverkest/.buildout/eggs/anybox.recipe.openerp-1.9.1-py2.7.egg/anybox/recipe/openerp/runtime/session.py:13: RuntimeWarning: This must be imported with a buildout openerp recipe driven sys.path
  "driven sys.path", RuntimeWarning)
Traceback (most recent call last):
  File "bin/upgrade_openerp", line 40, in <module>
    session = Session('/home/pverkest/openerp/client/odoo_client_buildout/etc/openerp.cfg', '/home/pverkest/openerp/client/odoo_client_buildout')
  File "/home/pverkest/.buildout/eggs/anybox.recipe.openerp-1.9.1-py2.7.egg/anybox/recipe/openerp/runtime/session.py", line 124, in __init__
    config.parse_config(['-c', conffile])
NameError: global name 'config' is not defined