Update extension.driver.php
Update extension.driver.php

- Use General::deleteFile, General::writeFile for the `subsectionmanager-storage` file
- Put the `subsectionmanager-storage` file in `CACHE`, as that is what it is
symphonists/subsectionmanager,frenkel/subsectionmanager,loremipson/subsectionmanager,symphonists/subsectionmanager,frenkel/subsectionmanager,loremipson/subsectionmanager