director: Fix shutdown_clients=no to not break

The director process must shut down even with with shutdown_clients=no.
Otherwise the two director processes will try to keep competing with each
others and log errors like:

director: Warning: Director 10.0.0.123:9090/right disconnected us with reason: Replacing with new incoming connection
director: Warning: Director 10.0.0.123:9090/right disconnected us with reason: Replacing with 10.0.0.124:9090

src/director/main.c

@@ -248,6 +248,11 @@ static void main_preinit(void)
 	struct ip_addr listen_ip;
 	in_port_t listen_port;
 
+	/* make sure we die with master even with shutdown_clients=no.
+	   otherwise there will be two director processes and everything is
+	   broken. it's only the login processes that need to stay alive. */
+	master_service_set_die_with_master(master_service, TRUE);
+
 	if (master_service_settings_get(master_service)->verbose_proctitle) {
 		to_proctitle_refresh =
 			timeout_add(1000, director_refresh_proctitle_timeout,