Make wxTextCtrlOleCallback destructor virtual to avoid g++ warnings.

This class doesn't really need a virtual dtor as it's never used
polymorphically, but add it to avoid g++ warnings about it.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77747 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/textctrl.cpp

@@ -156,7 +156,7 @@ class wxTextCtrlOleCallback : public IRichEditOleCallback
 {
 public:
     wxTextCtrlOleCallback(wxTextCtrl *text) : m_textCtrl(text), m_menu(NULL) {}
-    ~wxTextCtrlOleCallback() { DeleteContextMenuObject(); }
+    virtual ~wxTextCtrlOleCallback() { DeleteContextMenuObject(); }
 
     STDMETHODIMP ContextSensitiveHelp(BOOL WXUNUSED(enterMode)) { return E_NOTIMPL; }
     STDMETHODIMP DeleteObject(LPOLEOBJECT WXUNUSED(oleobj)) { return E_NOTIMPL; }