[freeciv-ai] Bug: infinite recursion in settler.c

[Jordi Negrevernis i Font <jorneg@xxxxxxxxxxx>]

   In 'auto_settler_findwork' the last line of the function can make a 
recursion.
   In current cvs is usual to see 'could not make city on (x,y) 
grassland'... So the code attempts to select another location and 
recurses to cuild that city.
   So, an easy fix is to place a flag as a parameter in 
'auto_settler_findwork', or investigate what fails in 'ai_do_build_city'.