[freeciv-ai] fix for strange goto code

["Per I. Mathisen" <per@xxxxxxxxxxx>]

There is a bug in cvs now that prevents ferries from returning home after
completed mission. This is directly related to the goto_is_sane() cleanup
previously committed.

The code that is buggy is in another place, though, and wasn't changed.
How it was ever correct is anybody's guess.

In any case, here is the fix. Please read & commit ASAP.

  - Per

gotosanitybug1.diff
Description: Text document