fix NameError in 1.8.0 (closes #224825)
Created originally on Bitbucket by agurney (Alexandre Fayolle)
Changesets for this Pull Request have not been imported, because it had been already declined on Bitbucket. Marked as closed by the import user.
There was a leftover underscore in a branch which likely was not exercised in the tests, causing a crash reported in https://www.logilab.org/ticket/224825