remobe backward compatibility for portals

mods/ITEMS/mcl_portals/portal_end.lua

@@ -4,11 +4,6 @@ local S = minetest.get_translator("mcl_portals")
 local SPAWN_MIN = mcl_vars.mg_end_min+70
 local SPAWN_MAX = mcl_vars.mg_end_min+98
 
-local PORTAL_ALPHA = 192
-if minetest.features.use_texture_alpha_string_modes then
-	PORTAL_ALPHA = nil
-end
-
 local mg_name = minetest.get_mapgen_setting("mg_name")
 
 local destroy_portal = function(pos)
@@ -81,7 +76,6 @@ minetest.register_node("mcl_portals:portal_end", {
 	-- This is 15 in MC.
 	light_source = 14,
 	post_effect_color = {a = 192, r = 0, g = 0, b = 0},
-	alpha = PORTAL_ALPHA,
 	after_destruct = destroy_portal,
 	-- This prevents “falling through”
 	collision_box = {

mods/ITEMS/mcl_portals/portal_nether.lua

@@ -30,7 +30,6 @@ local N_Y_MIN, N_Y_MAX			= mcl_vars.mg_bedrock_nether_bottom_min, mcl_vars.mg_be
 local O_DY, N_DY			= O_Y_MAX - O_Y_MIN + 1, N_Y_MAX - N_Y_MIN + 1
 
 -- Alpha and particles
-local ALPHA = minetest.features.use_texture_alpha_string_modes and 192
 local node_particles_allowed = minetest.settings:get("mcl_node_particles") or "none"
 local node_particles_levels = { none=0, low=1, medium=2, high=3 }
 local PARTICLES = node_particles_levels[node_particles_allowed]
@@ -263,7 +262,6 @@ minetest.register_node(PORTAL, {
 	drop = "",
 	light_source = 11,
 	post_effect_color = {a = 180, r = 51, g = 7, b = 89},
-	alpha = ALPHA,
 	node_box = {
 		type = "fixed",
 		fixed = {