QE65000 controller, avoid crash if saving I0 when no spectrum measure done

src/controllers/spectrometer/QE65000Controller.cpp

@@ -237,7 +237,7 @@ void QE65000Controller::setPlotName(int32 plotId) {
 void QE65000Controller::makeAutozero() {
 
 	// We do not do a measure... we just copy the last spectrum done as our intensity0
-	if (!spectroDriver->commandStatus.isRunning()) {
+	if (!spectroDriver->commandStatus.isRunning() && yData.getSize() == size()) {
 		y0Data.update(yData());
 		y0Data.setSize(size());