demux: mpegv: no need to initialize the es_format_t twice

It won't be modified during the demux_PacketizerNew() call.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/demux/mpeg/mpgv.c

@@ -129,7 +129,6 @@ static int Open( vlc_object_t * p_this )
     }
 
     /* create the output */
-    es_format_Init( &fmt, VIDEO_ES, VLC_CODEC_MPGV );
     p_sys->p_es = es_out_Add( p_demux->out, &fmt );
     if( p_sys->p_es == NULL )
     {