Qt4: don't use TS muxer with RTSP in sout wizard

Most RTSP clients expect native RTP and won't cope with Transport
Stream. Also, since RTSP takes care of RTP setup, there is little
benefit in having a single stream.

modules/gui/qt4/components/sout/sout_widgets.cpp

@@ -270,7 +270,6 @@ QString RTSPDestBox::getMRL( const QString& mux )
     SoutMrl m;
     m.begin( "rtp" );
     m.option( "sdp", sdp );
-    m.option( "mux", "ts" );
     m.end();
 
     return m.getMrl();