Hi,
Luca told me that you dont need to add this in the new RC3.
In this release this error is fixed.
If you did an update from an older RC to the newest and want to change the chmod automaticly, please take a look into the install/contrib folder, where you find a file which is called
reset_permissions.php
open that file, and there you find a line
$dir = 'files/album/otf/';
change it to whatever you need to change permissions to 0755, and then launch it from your root