FIX: wire did not disappear after disconnect

src/main/java/de/ph87/electro/circuit/CircuitPanelMouseAdapter.java

@@ -43,6 +43,7 @@ class CircuitPanelMouseAdapter extends MouseAdapter {
     if (event.getButton() == BUTTON3) {
       final Optional<Wire> wireOptional = circuitPanel.getCircuit().findWireByPosition(position);
       if (wireOptional.isPresent()) {
+        wireHover = null;
         circuitPanel.getCircuit().disconnect(wireOptional.get());
         circuitPanel.repaint();
         return;