[repository,tests] use the new connection api (part 1/2)
`add_info` should not play with the cnxset nor the mode.
Static analysis showed that:
* add_info is an internal api called with a non-none cnx.cnxset and
also in write mode
* only the altered test violated this assumption, which is now
somewhat documented
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))