fix moreores loading of tin ingot vs default tin ingot with backguard…

… compat

* real fix for mt-mods/technic_armor#7

3d_armor_technic/init.lua

@@ -37,7 +37,7 @@ if minetest.get_modpath("technic_worldgen") then
 	materials.carbon = {
 		name = S("Carbon Steel"),
 		craft_item = "technic:carbon_steel_ingot",
-		armor = 2.7,
+-		armor = 2.7,
 		heal = 10,
 		use = 100,
 		radiation = 40
@@ -54,11 +54,7 @@ end
 
 local tin_ingot
 
-if minetest.registered_items["default:tin_ingot"] then
-	tin_ingot = "default:tin_ingot"
-end
-
-if minetest.get_modpath("moreores") then
+if minetest.get_modpath("moreores") and minetest.registered_items["moreores:tin_ingot"] then
 	tin_ingot = "moreores:tin_ingot"
 	materials.silver = {
 		name = S("Silver"),
@@ -69,8 +65,8 @@ if minetest.get_modpath("moreores") then
 		radiation = 53
 	}
 end
-
-if tin_ingot then
+if minetest.get_modpath("default") and minetest.registered_items["default:tin_ingot"] then
+	tin_ingot = "default:tin_ingot"
 	materials.tin = {
 		name = S("Tin"),
 		craft_item = tin_ingot,