V4: make Scope uncopyable.

Copying will result in a dangling pointer.

Change-Id: I7f7e0df87326f43cf0ee5da6562726a5e3d2ca9c
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

src/qml/jsruntime/qv4scopedvalue_p.h

@@ -95,9 +95,11 @@ struct Scope {
 #ifndef QT_NO_DEBUG
     mutable int size;
 #endif
+
+private:
+    Q_DISABLE_COPY(Scope)
 };
 
-struct ScopedValue;
 struct ValueRef;
 
 struct ScopedValue