Fix request #6786: None column on the cardwall renderer is empty when the ui is in french

This occurs only when we browse the interface with french language.

Change-Id: I776dafe1a7aecf5893ae8aa207e542c1eb548d57
Merge commit 'refs/changes/70/2370/2' of http://gerrit.tuleap.net/tuleap into HEAD

* http://gerrit.tuleap.net/tuleap:
  Fix request #6786: None column on the cardwall renderer is empty when the ui is in french

Change-Id: I5fc1f53a8d4ac615078cdd19b7053018bd5c7031
This is Tuleap 6.12.99.100

Change-Id: Icdf3ba7269e2ac0392ea6440b5ee3c45e4afaa44