Prevent deletion of options that have children attached to them.

closes #562

app/Exceptions/Service/ServiceOption/HasChildrenException.php

@@ -0,0 +1,16 @@
+<?php
+/*
+ * Pterodactyl - Panel
+ * Copyright (c) 2015 - 2017 Dane Everitt <dane@daneeveritt.com>.
+ *
+ * This software is licensed under the terms of the MIT license.
+ * https://opensource.org/licenses/MIT
+ */
+
+namespace Pterodactyl\Exceptions\Service\ServiceOption;
+
+use Pterodactyl\Exceptions\DisplayException;
+
+class HasChildrenException extends DisplayException
+{
+}