player: deselect video track if initialization fails

This didn't have any consequences, other than suddenly reinitializing
video when it works again (such as with EDL timeline mixing video and
audio-only files).

mpvcore/player/video.c

@@ -165,6 +165,7 @@ err_out:
 no_video:
     uninit_player(mpctx, INITIALIZED_VCODEC | (opts->force_vo ? 0 : INITIALIZED_VO));
     cleanup_demux_stream(mpctx, STREAM_VIDEO);
+    mpctx->current_track[STREAM_VIDEO] = NULL;
     handle_force_window(mpctx, true);
     MP_INFO(mpctx, "Video: no video\n");
     return 0;