blockchain: use the version passed as parameter, not a new one

src/cryptonote_core/blockchain.cpp

@@ -1199,7 +1199,7 @@ bool Blockchain::validate_miner_transaction(const block& b, size_t cumulative_bl
     return false;
   }
   // From hard fork 2, we allow a miner to claim less block reward than is allowed, in case a miner wants less dust
-  if (m_hardfork->get_current_version() < 2)
+  if (version < 2)
   {
     if(base_reward + fee != money_in_use)
     {