fixed return 0 for "getLastSort" when queue empty

dist/assets/classes/queue.class.php

@@ -23,7 +23,7 @@ class queue {
       return 'MYSQL_BIND_RESULTS';
     } else {
       if ( !$stmt->fetch() ) {
-        return 'MYSQL_FETCH';
+        return 0;
       } else {
         return $res;
       }

src/assets/classes/queue.class.php

@@ -23,7 +23,7 @@ class queue {
       return 'MYSQL_BIND_RESULTS';
     } else {
       if ( !$stmt->fetch() ) {
-        return 'MYSQL_FETCH';
+        return 0;
       } else {
         return $res;
       }