ipc: always include old property in workspace events

sway/ipc-server.c

@@ -298,14 +298,12 @@ void ipc_event_workspace(struct sway_container *old,
 	wlr_log(WLR_DEBUG, "Sending workspace::%s event", change);
 	json_object *obj = json_object_new_object();
 	json_object_object_add(obj, "change", json_object_new_string(change));
-	if (strcmp("focus", change) == 0) {
 	if (old) {
 		json_object_object_add(obj, "old",
 				ipc_json_describe_container_recursive(old));
 	} else {
 		json_object_object_add(obj, "old", NULL);
 	}
-	}
 
 	if (new) {
 		json_object_object_add(obj, "current",