Serials: Caption/pattern wizard use enum fields for chronology when no enum

MFHD spec says that when there are no ‡a - ‡f enumeration captions, any
chronology captions should move back from their usual ‡i - ‡m places
back into enumeration space.

The predictions engine we already have deals with this better than with
the wrong patterns we were creating before, e.g.:

853 20 ‡81 ‡i(year) ‡j(month) ‡wm

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>
Signed-off-by: Dan Wells <dbw2@calvin.edu>