Fix bug getting the arp definition from metarefresh config sets

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@1512 44740490-163a-0410-bde0-09ae8108e29a

modules/metarefresh/hooks/hook_cron.php

@@ -51,9 +51,8 @@ function metarefresh_hook_cron(&$croninfo) {
 					break;
 			}
 
-			
-			if (array_key_exists('arp', $set)) {
-				$arpconfig = SimpleSAML_Configuration::loadFromArray($set['arp']);
+			if ($set->hasValue('arp')) {
+				$arpconfig = SimpleSAML_Configuration::loadFromArray($set->getValue('arp'));
 				$metaloader->writeARPfile($arpconfig);
 			}
 		}