do not add the "\xFF" "VERSION" key --- it should only be added once
ALL entries have been updated.
While I'm here, correct the logic that detects whether or not the
user-ID has changed so that it works even if all entries have not
yet been updated to the new format.
Users missing-in-action were
Reported by: tjr, Vallo Kallaste <vallo@estcard.ee>,
leafy <leafy@leafy.idv.tw>
Sponsored by: DARPA, Network Associates Laboratories
257ca75f51