*Apply tenacity buff on vehicles of wintergrasp.

*Fix the bug that tenacity is not applied on horde players.

--HG--
branch : trunk

src/game/SpellEffects.cpp

@@ -3295,7 +3295,8 @@ void Spell::EffectSummonType(uint32 i)
                         return;
 
                     //vehicle->SetUInt64Value(UNIT_FIELD_SUMMONEDBY, m_caster->GetGUID());
-                    vehicle->setFaction(m_caster->getFaction());
+                    if(m_originalCaster)
+                        vehicle->setFaction(m_originalCaster->getFaction());
                     vehicle->SetUInt32Value(UNIT_CREATED_BY_SPELL, m_spellInfo->Id);
                     break;
                 }