Core/Loot: Reimplement the proper check for loot recipient to prevent rewarding loot without tagging the creature by the player.

Also fix the related skinning problem, and do not set the skinnable flag for creatures without any loot recipient.

--HG--
branch : trunk

src/server/game/Entities/Player/Player.cpp

@@ -8464,10 +8464,7 @@ void Player::SendLoot(uint64 guid, LootType loot_type)
             // the player whose group may loot the corpse
             Player *recipient = creature->GetLootRecipient();
             if (!recipient)
-            {
-                creature->SetLootRecipient(this);
-                recipient = this;
-            }
+                return;
 
             if (!creature->lootForBody)
             {