rfalke: Correct the way how the total trade of trade...

This is an automated notification of a change to freeciv cvs, 
on Sun Mar  2 07:26:14 PST 2003 = Sun Mar  2 15:26:14 2003 (GMT)
by Raimar Falke <rf13@xxxxxxxxxxxxxxxxx>

---- Files affected:

freeciv/common/aicore cm.c

---- Log message:
      Tag: HEAD

Correct the way how the total trade of trade routes is
calculated. Previously the current tile_trade was used. Correct
however is to use the estimated maximal tile_trade.

Reported by Mateusz Stefek <matusik_s@xxxxx>. Patch from me.