autodel: use VLC_TS_INVALID (refs #3135)

modules/stream_out/autodel.c

@@ -126,7 +126,7 @@ static sout_stream_id_t * Add( sout_stream_t *p_stream, es_format_t *p_fmt )
 
     p_es->fmt = *p_fmt;
     p_es->id = NULL;
-    p_es->i_last = 0;
+    p_es->i_last = VLC_TS_INVALID;
     p_es->b_error = false;
     TAB_APPEND( p_sys->i_es_num, p_sys->pp_es, p_es );