Prevent passthrough and node etc. failure in generator at startup due to proxy recruit change.

src/generator.c

@@ -2020,12 +2020,14 @@ out:
 	if (ret) {
 		proxy_instance_t *parent = proxi->parent;
 
+		if (parent) {
 			mutex_lock(&parent->proxy_lock);
 			parent->recruit -= proxi->clients_per_proxy;
 			if (parent->recruit < 0)
 				parent->recruit = 0;
 			mutex_unlock(&parent->proxy_lock);
 		}
+	}
 
 	return ret;
 }