Comment # 1 on bug 1097867 from Ignaz Forster

The option was not needed at all, doing nothing in practice: As the mounted
/etc directory was used for synchronization the attribute wasn't visible
anyway. This was a leftover from the dracut overlay handling.

The option was just removed for transactional-update 2.10
(https://github.com/openSUSE/transactional-update/commit/bb79403a0c310b81f25228ec74853223ab02b45f).