SimpleQuery: Deep clone the filter when cloning the query

library/Icinga/Data/Db/DbQuery.php

@@ -381,6 +381,7 @@ class DbQuery extends SimpleQuery
 
     public function __clone()
     {
+        parent::__clone();
         $this->select = clone $this->select;
     }
 

library/Icinga/Data/SimpleQuery.php

@@ -550,4 +550,12 @@ class SimpleQuery implements QueryInterface, Queryable, Iterator
     {
         return $this->columns;
     }
+
+    /**
+     * Deep clone self::$filter
+     */
+    public function __clone()
+    {
+        $this->filter = clone $this->filter;
+    }
 }