Core/Loot: Skinning improvements

* Set skinnable flag only after all loot was taken
* Creatures are skinnable only once - after skinning, the player only has to loot the creature again if he did not take all skinning loot

src/server/game/Entities/Unit/Unit.cpp

@@ -15271,11 +15271,8 @@ void Unit::Kill(Unit* victim, bool durabilityLoss)
         if (creature)
         {
             Loot* loot = &creature->loot;
-            if (creature->lootForPickPocketed)
-            {
+            if (creature->loot.loot_type == LOOT_PICKPOCKETING)
                 creature->ResetPickPocketRefillTimer();
-                creature->lootForPickPocketed = false;
-            }
 
             loot->clear();
             if (uint32 lootid = creature->GetCreatureTemplate()->lootid)
@@ -15394,9 +15391,12 @@ void Unit::Kill(Unit* victim, bool durabilityLoss)
         if (!creature->IsPet())
         {
             creature->DeleteThreatList();
-            CreatureTemplate const* cInfo = creature->GetCreatureTemplate();
-            if (cInfo && (cInfo->lootid || cInfo->maxgold > 0))
+
+            // must be after setDeathState which resets dynamic flags
+            if (!creature->loot.empty())
                 creature->SetFlag(UNIT_DYNAMIC_FLAGS, UNIT_DYNFLAG_LOOTABLE);
+            else
+                creature->AllLootRemovedFromCorpse();
         }
 
         // Call KilledUnit for creatures, this needs to be called after the lootable flag is set