[cwconfig] Trim down allowed exceptions in gettext language setting
I can't see any valid reason to pass on ImportError and AttributeError. In
particular, the latter shadowed a Python 3 error until 4f43e64603ef.
Document: cubicweb-doc
Title: CubicWeb Documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/python-cubicweb-documentation/html/index.html
Files: /usr/share/doc/python-cubicweb-documentation/html/*