[web/form] Relax condition for non-translating field names we should test true condition instead of None, so if one raise a ValidationError using an empty string as 'no-field' marker instead of None, we don't get the PO file header that gettext likes to return when one attempt to translate an empty string.

[bdist_wheel]
universal = 1

[check-manifest]
ignore =
  debian
  debian/*
  cubicweb.spec
  __pkginfo__.py