Apply transparency 2 testliquids (MT 5.4.0 compat)

mods/supplemental/init.lua

@@ -176,8 +176,6 @@ minetest.register_craft({
 
 -- 8 viscosity example liquids
 for v=0,7 do
-	local alpha = 120 + v*15
-
 	minetest.register_node("supplemental:liquid"..v, {
 		description = string.format(S("flowing test liquid %i"), v),
 		inventory_image = minetest.inventorycube("supplemental_testliquid"..v..".png"),
@@ -194,7 +192,7 @@ for v=0,7 do
 			},
 
 		},
-		alpha = alpha,
+		use_texture_alpha = "blend",
 		paramtype = "light",
 		paramtype2 = "flowingliquid",
 		walkable = false,
@@ -222,7 +220,7 @@ for v=0,7 do
 			},
 		},
 		tiles = {"supplemental_testliquid"..v..".png",},
-		alpha = alpha,
+		use_texture_alpha = "blend",
 		paramtype = "light",
 		walkable = false,
 		pointable = false,