Fixed #5331 Disallow 0 as website harddisk quota value

interface/web/sites/lib/lang/de_web_vhost_domain.lng

@@ -152,4 +152,5 @@ $wb['https_port_error_regex'] = 'HTTPS Port invalid.';
 $wb['enable_pagespeed_txt'] = 'Enable PageSpeed';
 $wb['log_retention_txt'] = 'Log-Dateien Aufbewahrungszeit';
 $wb['log_retention_error_regex'] = 'Aufbewahrungszeit in Tagen (Erlaubte Werte: min. 0 - max. 9999)';
+$wb['limit_web_quota_not_0_txt'] = 'Harddisk Quota kann nicht 0 sein.';
 ?>

interface/web/sites/lib/lang/en_web_vhost_domain.lng

@@ -157,4 +157,5 @@ $wb['https_port_error_regex'] = 'HTTPS Port invalid.';
 $wb['enable_pagespeed_txt'] = 'Enable PageSpeed';
 $wb['log_retention_txt'] = 'Logfiles retention time';
 $wb['log_retention_error_regex'] = 'Retention time in days (allowed values: min. 0 - max. 9999)';
+$wb['limit_web_quota_not_0_txt'] = 'Harddisk Quota cannot be set to 0.';
 ?>

interface/web/sites/web_vhost_domain_edit.php

@@ -1065,6 +1065,11 @@ class page_action extends tform_actions {
 			}
 			
 			if($this->_vhostdomain_type == 'domain') {
+				//* ensure that quota value is not 0 when vhost type = domain
+				if(isset($_POST["hd_quota"]) && $_POST["hd_quota"] == 0) {
+					$app->tform->errorMessage .= $app->tform->lng("limit_web_quota_not_0_txt")."<br>";
+				}
+				
 				//* Check the website quota of the client
 				if(isset($_POST["hd_quota"]) && $client["limit_web_quota"] >= 0 && $_POST["hd_quota"] != $old_web_values["hd_quota"]) {
 					$tmp = $app->db->queryOneRecord("SELECT sum(hd_quota) as webquota FROM web_domain WHERE domain_id != ? AND type = 'vhost' AND ".$app->tform->getAuthSQL('u'), $this->id);