message: Don't output non-existent owner string
diff: @@ -92,7 +92,10 @@ void HoI4State::output(const string& _filename) const
  }
  out << "\n";
  out << "\thistory={\n";
  + if (ownerTag != "")
  + {
  out << "\t\towner = " << ownerTag << "\n";
  + }
  if ((victoryPointValue > 0) && (victoryPointPosition != 0))
  {
  if (Configuration::getDebug())
  