Allow minetest.get_player_by_name while leaving

Allow minetest.registered_on_leaveplayers to use minetest.get_player_by_name while the player is leaving.

core.lua

@@ -124,8 +124,6 @@ cloaking.cloak = function(player)
     player:set_properties({visual_size = {x = 0, y = 0}, collisionbox = {0,0,0,0,0,0}})
     p:set_nametag_attributes({text = " "})
     
-    cloaked_players[victim] = true
-    
     local t = nil
     if areas and areas.hud and areas.hud[victim] then
         t = areas.hud[victim]
@@ -137,6 +135,8 @@ cloaking.cloak = function(player)
         end
     end
     
+    cloaked_players[victim] = true
+    
     if t then
         areas.hud[victim] = t
         p:hud_change(areas.hud[victim].areasId, "text", "Cloaked")