Core/Unit: Fix leave combat timer - original patch by Laise

Needs further testing, give feedback if wrong.

--HG--
branch : trunk

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

@@ -253,7 +253,7 @@ void Unit::Update(uint32 p_time)
         {
             // m_CombatTimer set at aura start and it will be freeze until aura removing
             if (m_CombatTimer <= p_time)
-                ClearInCombat();
+                CombatStop();
             else
                 m_CombatTimer -= p_time;
         }