Fixed another harmless but annoying leaks

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@9888 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/states_screens/addons_screen.cpp

@@ -114,6 +114,14 @@ void AddonsScreen::init()
 
 // ----------------------------------------------------------------------------
 
+void AddonsScreen::unloaded()
+{
+    delete m_icon_bank;
+    m_icon_bank = NULL;
+}
+
+// ----------------------------------------------------------------------------
+
 void AddonsScreen::tearDown()
 {
     // return tab stop to the center when leaving this screen!!

src/states_screens/addons_screen.hpp

@@ -75,6 +75,8 @@ public:
     /** \brief implement callback from parent class GUIEngine::Screen */
     virtual void loadedFromFile();
 
+    virtual void unloaded();
+    
     /** \brief implement callback from parent class GUIEngine::Screen */
     virtual void eventCallback(GUIEngine::Widget* widget, const std::string& name, const int playerID);