matusik: Don't resend all ex-allied city in remove_a...

This is an automated notification of a change to freeciv cvs, 
on Wed Sep 22 00:17:57 PDT 2004 = Wed Sep 22 07:17:57 2004 (GMT)
by Mateusz Stefek <matusik_s@xxxxx>

---- Files affected:

freeciv/server unittools.c

---- Log message:
      Tag: HEAD

Don't resend all ex-allied city in remove_allied_visibility(), send only those 
known and seen.
Reported by Marek Baczek BaczyÅ?ski in PR#10236; patch by me