[CLEANUP] Make setUp/tearDown protected in the documentation

Change-Id: I435fffbfba81fde7a986a27d6d4b35de9426438b
Reviewed-on: http://review.typo3.org/35449
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>