bar: free old position when changing

sway/commands/bar/position.c

@@ -17,6 +17,7 @@ struct cmd_results *bar_cmd_position(int argc, char **argv) {
 		if (strcasecmp(valid[i], argv[0]) == 0) {
 			wlr_log(WLR_DEBUG, "Setting bar position '%s' for bar: %s",
 					argv[0], config->current_bar->id);
+			free(config->current_bar->position);
 			config->current_bar->position = strdup(argv[0]);
 			return cmd_results_new(CMD_SUCCESS, NULL, NULL);
 		}