Rename gettext to cwgettext, use stdlib gettext cubicweb/gettext.py was a copy of Python 2.6's gettext.py with the context patch from bug https://bugs.python.org/issue2504 Instead of keeping that full copy, just inherit from gettext.GNUTranslations and add the context-related stuff.

import ConfigParser
try:
    undo_actions = config.cfgfile_parser.get('MAIN', 'undo-support', False)
except ConfigParser.NoOptionError:
    pass # this conf. file was probably already migrated
else:
    config.global_set_option('undo-enabled', bool(undo_actions))