don't give debug messages about WM_MDISETMENU failure if there was no error

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@46111 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/mdi.cpp

@@ -1395,7 +1395,11 @@ static void MDISetMenu(wxWindow *win, HMENU hmenuFrame, HMENU hmenuWindow)
                             (WPARAM)hmenuFrame,
                             (LPARAM)hmenuWindow) )
         {
-            wxLogLastError(_T("SendMessage(WM_MDISETMENU)"));
+#ifdef __WXDEBUG__
+            DWORD err = ::GetLastError();
+            if ( err )
+                wxLogApiError(_T("SendMessage(WM_MDISETMENU)"), err);
+#endif // __WXDEBUG__
         }
     }