(guerrilla): Give wandering che inexact, somewhat randomized

(guerrilla): Give wandering che inexact, somewhat randomized
information on military.  Closes #750533.  Why?  Wandering che pick a
sector with minimal military from the adjacent sectors that can get
che.  Ties are broken in favour of the first sector examined.  Since
sectors are examined in the order given by by diroff[], che prefer
directions with low index in diroff[].  This tends to channel che
towards the northeast.  But the change makes ties very unlikely.