[469b] UnrealEd set wrong iWarpZone during build

[SeriousBuggie]

Reproduce:

1. Open DM-AMC-Modular.zip
2. Build only geometry.
3. Select WarpZoneInfo3, Trigger2.
   It is easy do from top view:
   
4. Copy selected actors as text.

Begin Actor Class=WarpZoneInfo Name=WarpZoneInfo3
     iWarpZone=2
Begin Actor Class=Trigger Name=Trigger2
     Region=(Zone=ZoneInfo'MyLevel.ZoneInfo3',iLeaf=1871,ZoneNumber=4)

Expected result: Trigger ZoneNumber match WarpZoneInfo iWarpZone. Game work, portal not produce HOM.
Actual result: Trigger ZoneNumber (4) not match WarpZoneInfo iWarpZone (2). Game stuck and crash, because try draw portal itself in endless recursion.

Via EDITACTOR Name=WarpZoneInfo3 iWarpZone can be manually set to 4. After that portal work as intended, no any crash, HOM or stuck.

[SeriousBuggie]

This happen because iZonePortalSurf not set for FPortal. So basically this warp zones ignored during update and iWarpZone not set and left (any) value.
So it can left to same zone as actor itself, which make endless recursion on draw.