we do not need to queue ::redisplay_track_Views() for track height changes

This may be incorrect, since track height changes may be driven
directly (e.g. via menu items) rather than by mouse drags. This may
need revisiting and there may need to be a way to separate dragged height
changes from others.

gtk2_ardour/editor.cc

@@ -5961,7 +5961,7 @@ Editor::redisplay_track_views ()
 void
 Editor::handle_gui_changes (string const & what, void*)
 {
-	if (what == "track_height" || what == "visible_tracks") {
+	if (what == "visible_tracks") {
 		queue_redisplay_track_views ();
 	}
 }