Fix apparent session leak in services.

It appears that after successful completion of a JS service, the
TLS session is never destroyed.

If this fix isn't valid for #707, we should see a bunch of
"Destroying a session (...) that's not in sess_list" log messages

Thanks Keyop!

src/sbbs3/services.c

@@ -1260,6 +1260,8 @@ static void js_service_thread(void* arg)
 		lprintf(LOG_INFO,"%04d %s [%s] JavaScript service thread terminated (%lu clients remain, %lu total, %lu served)"
 			,socket, service->protocol, client.addr, remain, active_clients(), service->served);
 
+	if (service_client.tls_sess != -1)
+		destroy_session(lprintf, service_client.tls_sess);
 	client_off(socket);
 	close_socket(socket);
 }