[code] Invalid the script node. If we don't, layouting the subviews

would use the deleted python heap.
using the python heap before

Change-Id: Icf77e7723d843ff415b8e2da11f5ab64eba48aef

apps/code/variable_box_controller.cpp

@@ -62,6 +62,9 @@ void VariableBoxController::ContentViewController::viewWillAppear() {
 
 void VariableBoxController::ContentViewController::viewDidDisappear() {
   m_selectableTableView.deselectTable();
+  for (int i = 0; i < k_maxScriptNodesCount; i++) {
+    m_scriptNodes[i] = ScriptNode();
+  }
   ViewController::viewDidDisappear();
 }