Revert "[BUGFIX] LocalDriver needs to respect "is_writeable""

This change broke the tests

This reverts commit af01ce40933c79162dfb9984d948363fc6199811

Change-Id: I29c9c5893e42278b7e1f645e60874b2cdb20074c
Reviewed-on: https://review.typo3.org/17499
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel