Cheating netconfig by using local 'bind' as resolver temporarily

- This is caused by documented netconfig behavior while FATE#309036
  requests some manual changes that might put the system into
  inconsistency and thus make netconfig skip updating the system
  configuration files
- This change uses approach acceptabe to netconfig - temporarily
  switching to state when files are updates by that tool and then
  switching back to original user-defined resolver
- Both forwarders.conf and the system are then updated to the latest
  greatest settings
Adapted testsuite to the latest changes

- Cheating netconfig