Don't store land unit stats in struct lndstr, part 2

struct lndstr members lnd_spy, lnd_rad, lnd_ammo, lnd_fuelc,
lnd_fuelu, lnd_maxlight, lnd_maxlight are mere copies of struct
lchrstr members l_spy, l_rad, l_ammo, l_fuelc, l_fuelu, l_nxlight,
l_nland.  Remove them.

Make land unit selectors spy, rmax, ammo, fuelc, fuelu, maxlight
virtual.

src/lib/commands/rada.c

@@ -112,7 +112,8 @@ radar(short type)
 		    pr("Units on ships can't use radar!\n");
 		    continue;
 		}
-		tech = techfact(item.land.lnd_tech, item.land.lnd_spy);
+		tech = techfact(item.land.lnd_tech,
+				lchr[item.land.lnd_type].l_spy);
 	    }
 
 	    pr("%s at ", obj_nameof(&item.gen));