Update to Freeciv server r35473.
Update to Freeciv server r35473.

Freeciv commit message:
JSON protocol: fix sub field sending memory leak.

Steal the references to values created inline when put inside an object by
using json_object_set_new() rather than json_object_set().

Found with Valgrind.
Reported by Andreas Røsdal

See hrm Bug #658386

andreasrosdal/freeciv-web,andreasrosdal/freeciv-web,andreasrosdal/freeciv-web,andreasrosdal/freeciv-web,andreasrosdal/freeciv-web