Don't use automatic supply to avoid starvation at the update

Food supply during update adds complexity to the update.  How much
good it does to players is highly doubtful; certainly nobody can rely
on it.  It isn't covered by the starvation command.  Starving ships or
land units can steal enough food from their sector to make it starve,
too.  Finally, the supply code is notoriously hard to use correctly.
We don't know of issues with the update's use, but we haven't
convinced ourselves that there aren't any either.

src/lib/update/human.c

@@ -84,13 +84,6 @@ do_feed(struct sctstr *sp, struct natstr *np, short *vec,
 		    /* Conjure up 1f to make life easier for the player */
 		    manna = vec[I_FOOD] = 1;
 	    }
-	    if (vec[I_FOOD] < needed && sp->sct_own == sp->sct_oldown) {
-		/* steal food from warehouses, headquarters,
-		   supply ships in port, or supply units */
-		vec[I_FOOD] = supply_commod(sp->sct_own,
-					    sp->sct_x, sp->sct_y,
-					    I_FOOD, needed);
-	    }
 	}
 	starved = feed_people(vec, etu);
 	if (starved > 0) {