Makes R-walls double plasteel

Makes R-walls double plasteel like on master, adjusts plasteel integrity
so that R-walls have the same health as on master as well.

code/game/turfs/simulated/wall_types.dm

@@ -1,7 +1,7 @@
 /turf/simulated/wall/r_wall
 	icon_state = "rgeneric"
 /turf/simulated/wall/r_wall/New(var/newloc)
-	..(newloc, DEFAULT_WALL_MATERIAL,"plasteel") //3strong
+	..(newloc, "plasteel","plasteel") //3strong
 
 /turf/simulated/wall/cult
 	icon_state = "cult"

code/modules/materials/materials.dm

@@ -292,6 +292,7 @@ var/list/name_to_material
 /material/steel
 	name = DEFAULT_WALL_MATERIAL
 	stack_type = /obj/item/stack/material/steel
+	integrity = 150
 	icon_base = "solid"
 	icon_reinf = "reinf_over"
 	icon_colour = "#666666"
@@ -305,7 +306,7 @@ var/list/name_to_material
 /material/plasteel
 	name = "plasteel"
 	stack_type = /obj/item/stack/material/plasteel
-	integrity = 800
+	integrity = 400
 	melting_point = 6000
 	icon_base = "solid"
 	icon_reinf = "reinf_over"