Fixes db quota (typo)

Author: Linus9000

server/lib/classes/cron.d/300-quota_notify.inc.php

@@ -442,7 +442,7 @@ public function onRunJob() {
 								else $used_ratio = 0;
 
 								//* send notifications only if 90% or more of the quota are used
-								if($used_ratio > 0.9 && $user_ratio != 0) {
+								if($used_ratio > 0.9 && $used_ratio != 0) {
 
 									//* could a notification be sent?
 									$send_notification = false;