Fix CVehicleSA::BlowUp crash (#4058)

Fix BlowUp crash

Author: TheNormalnij

Client/game_sa/CVehicleSA.cpp

@@ -1123,7 +1123,7 @@ CDamageManager* CVehicleSA::GetDamageManager()
 
 void CVehicleSA::BlowUp(CEntity* pCreator, unsigned long ulUnknown)
 {
-    GetVehicleInterface()->BlowUpCar(pCreator->GetInterface(), ulUnknown);
+    GetVehicleInterface()->BlowUpCar(pCreator ? pCreator->GetInterface() : nullptr, ulUnknown);
 }
 
 void CVehicleSA::FadeOut(bool bFadeOut)

Client/mods/deathmatch/logic/CClientVehicle.cpp

@@ -908,7 +908,7 @@ void CClientVehicle::Blow(VehicleBlowFlags blow)
         // "Fuck" the car completely, so we don't have weird client-side jumpyness because of differently synced wheel states on clients
         FuckCarCompletely(true);
 
-        m_pVehicle->BlowUp(NULL, 0);
+        m_pVehicle->BlowUp(nullptr, 0);
 
         // Blowing up a vehicle will cause an explosion in the original game code, but we have a hook in place,
         // which will prevent the explosion and forward the information to the server to relay it to everyone from there.