Remove EBCDIC remnants
Remove 'osfiletype' remnants

Even when this was finally removed in b2b920f20e7690fd4e5a800f89723409a3438768
6 months ago, it had already been disabled for a while. Due to this,
just remove all remnants of the option as opposed to putting a
placeholder like what was done for 'shortname'and 'cryptmethod'.
Remove RISC OS remnants