nova-manage project zipfile throws AttributeError

Exporting credential with nova-manage project zipfile <project-id> <user-id> throws an AttributeError.

Traceback (most recent call last):
  File "bin/nova-manage", line 290, in <module>
    main()
  File "bin/nova-manage", line 282, in main
    fn(*argv)
  File "bin/nova-manage", line 210, in zipfile
    zip_file = self.manager.get_credentials(project_id, user_id)
  File "/home/martin/openstack/nova/nova/auth/manager.py", line 691, in get_credentials
    rc = self.__generate_rc(user.access, user.secret, pid)
AttributeError: 'NoneType' object has no attribute 'access'

auth/manager.py excepts:
def get_credentials(self, user, project=None):

but bin/nova-manage calls get_credentials with wrong parameter order (swapped project_id and user_id):
zip_file = self.manager.get_credentials(project_id, user_id)