[Freeciv-Dev] (PR#12256) return of the unit_list_size assert

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://bugs.freeciv.org/Ticket/Display.html?id=12256 >

Attached to the ticket is a better savegame (submarine2) for
demonstrating the problem.

The submarine near banam is adjacent to an enemy sub which is also
within vision of another friendly sub.  Disband the adjacent sub and the
enemy sub should, but does not, disappear from sight.  Under the patch
this is fixed.

-jason