People in sectors get plagued, then taxed or paid, then fed. People
on ships and land units get paid, then fed, then plagued. Sectors
were messed up when Empire 3 made the update code work for budget.
Change sectors back to how they worked before Empire 3: move do_feed()
from produce_sect() to prepare_sects(), and delay do_plague() until
after do_feed(). People in sectors now get taxed, paid and fed even
when they die of the plague, just like they do on ships and land
units.
Because do_plague() now runs after populace(), the latter's handling
of people dying off doesn't cover plague anymore. Delay it to the
very end of prepare_sects().
Additionally, move feeding and plaguing from upd_ship(), upd_land() to
prep_ship(), prep_land(), for consistency with sectors.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>