Clean up suspicious coordinate system use in unit_put()

It showed unit coordinates in unit's coordinate system instead of the
actor's.  Fortunately, they're the same, since it is reachable only
for non-zero actor, only shp_nav_one_sector(), lnd_mar_one_sector()
and sail_nav_fleet() pass that, and even deities can't navigate
foreign ships or march foreign land units.

src/lib/subs/unitsub.c

@@ -116,7 +116,7 @@ unit_put(struct emp_qelem *list, natid actor)
 	    continue;
 	if (actor) {
 	    mpr(actor, "%s stopped at %s\n", obj_nameof(unit),
-		xyas(unit->x, unit->y, unit->own));
+		xyas(unit->x, unit->y, actor));
 	    if (unit->ef_type == EF_LAND) {
 		if (ulp->mobil < -127)
 		    ulp->mobil = -127;