Remove unnecessary SetAutoLayout(true) calls

There is no need to call SetAutoLayout() explicitly after (or just
before) calling SetSizer() with a valid sizer pointer, as SetSizer()
already enables automatic layout, so just drop the useless calls.

No real changes.

src/generic/msgdlgg.cpp

@@ -217,7 +217,6 @@ void wxGenericMessageDialog::DoCreateMsgdialog()
     if ( sizerBtn )
         topsizer->Add(sizerBtn, 0, wxEXPAND | wxALL, 10 );
 
-    SetAutoLayout( true );
     SetSizer( topsizer );
 
     topsizer->SetSizeHints( this );