[dataimport, migration] more fixes in the spirit of a6c32edabc8d:
[entity, metadata] huuum, use resolvable url as cwuri... And fix existing ones.
Closes #3390388
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))