will allow people with old config options to either have it just work
(if config is new enough), or get a version error (if their config is
about 7.0 or newer) rather than getting a cryptic error about
duplicated options in the options file, or getting an error about an
unknown option, at which point they'd update their config file only to
learn they need a new config, only to learn they didn't really need to
update their config file... All this because our version checking was
in the wrong place for the past decade...
# hopefully this is the last change, and we'll be able to config with an
# 8.0 GENERIC file on stable/8 after I merge this change and add the
# compat options.
MFC after: 3 days
4bc2b0b76d