Treat the `i` volume option like `k` when choosing the Unix-side
case for the automatically created SYS directories.
With a volume configured as `itO` (ignore case, trustees, OS/2 LFN),
the server currently recreates uppercase directories such as LOGIN,
PUBLIC, SYSTEM and MAIL on startup, even when the installed tree uses
lowercase login/public/system/mail. This leaves duplicate host
directories that appear as ambiguous entries from DOS clients.
Use lowercase Unix names for the auto-created SYS directories when
the volume is configured either as downshift (`k`) or ignore-case (`i`).
07ee7fa659