[doc] one must now manipulate the req.session.data dict (closes #2842345)
instead of deprecated get/set/del_session_data methods.
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))