[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.

addressbook
basket
blog
book
calendar
comment
company
email
file
folder
i18ncontent
keyword
link
mailinglist
person
tag
timeseries
vcsfile