Fix strict standards warnings

lib/MDB2/Driver/sqlite3.php

@@ -1221,7 +1221,7 @@ class MDB2_Statement_sqlite3 extends MDB2_Statement_Common
             return $affected_rows;
         }
 
-        $result =& $this->db->_wrapResult($result, $this->result_types,
+        $result = $this->db->_wrapResult($result, $this->result_types,
             $result_class, $result_wrap_class, $this->limit, $this->offset);
         $this->db->debug($this->query, 'execute', array('is_manip' => $this->is_manip, 'when' => 'post', 'result' => $result));
         return $result;