Qt4: disable the crashy embedded video(!)

I don't know if it's a Qt4 interface bug and/or an X11 output bug, but
it causes frequent crashes with several users (and most of them don't
know about --no-embedded-video).
(cherry picked from commit fff7615f)

modules/gui/qt4/qt4.cpp

@@ -213,9 +213,11 @@ vlc_module_begin();
 
         set_callbacks( OpenDialogs, Close );
 
+#if 0
     add_submodule();
         set_capability( "vout window", 50 );
         set_callbacks( WindowOpen, WindowClose );
+#endif
 vlc_module_end();
 
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