fix metricprovider (expect array)

app/Libs/Zimbra/Components/Api/Soap/Repository/DistributionLists.php

@@ -33,6 +33,7 @@ class DistributionLists extends AbstractRepository
 
         $accounts = $result->getResponseBody()['GETALLDISTRIBUTIONLISTSRESPONSE']['DL'];
 
+        $tmp = array();
         /**
          * API return one or araay with accounts
          */