[HttpFoundation] use insert or replace for sqlite session handler

Author: Tobion

src/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php

@@ -236,6 +236,8 @@ private function getMergeSql()
                 return "MERGE INTO $this->table USING (SELECT 'x' AS dummy) AS src ON ($this->idCol = :id) " .
                     "WHEN NOT MATCHED THEN INSERT ($this->idCol, $this->dataCol, $this->timeCol) VALUES (:id, :data, :time) " .
                     "WHEN MATCHED THEN UPDATE SET $this->dataCol = :data;";
+            case 'sqlite':
+                return "INSERT OR REPLACE INTO $this->table ($this->idCol, $this->dataCol, $this->timeCol) VALUES (:id, :data, :time)";
         }
 
         return null;