- degrade electrical XML SG_ALERT to SG_WARN. The reason why this is output

- degrade electrical XML SG_ALERT to SG_WARN. The reason why this is output
  at all is that this method is meant to be deprecated. But if it doesn't
  say that, and there's no generic replacement at all, then it's rather
  pointless.
- simplify parameter initialization (The old code copied from Instrumentation/
  but has been simplified there in the same manner a few months ago
  The new method is less picky about additional nodes ane outputs less
  pointless alerts. If there shall really be a check for that, then
  this should be a separate function. But it's nowhere else done in fgfs.