Remove useless wxMenu::Break() override in wxOSX

There is no real need to override a method not doing anything by default
just to do nothing in it explicitly.

include/wx/osx/menu.h

@@ -34,8 +34,6 @@ public:
 
     virtual ~wxMenu();
 
-    virtual void Break() wxOVERRIDE;
-
     virtual void SetTitle(const wxString& title) wxOVERRIDE;
 
     bool ProcessCommand(wxCommandEvent& event);

src/osx/menu_osx.cpp

@@ -88,11 +88,6 @@ WXHMENU wxMenu::GetHMenu() const
     return NULL;
 }
 
-void wxMenu::Break()
-{
-    // not available on the mac platform
-}
-
 void wxMenu::SetAllowRearrange( bool allow )
 {
     m_allowRearrange = allow;