tx_pool: remove transactions if they're in the blockchain

When starting up, if the pool state was not saved, the pool
might contain transactions which made it into the blockchain,
so these need removing

src/cryptonote_core/tx_pool.cpp

@@ -717,8 +717,16 @@ namespace cryptonote
     size_t n_removed = 0;
     size_t tx_size_limit = get_transaction_size_limit(version);
     for (auto it = m_transactions.begin(); it != m_transactions.end(); ) {
+      bool remove = false;
       if (it->second.blob_size >= tx_size_limit) {
-        LOG_PRINT_L1("Transaction " << get_transaction_hash(it->second.tx) << " is too big (" << it->second.blob_size << " bytes), removing it from pool");
+        LOG_PRINT_L1("Transaction " << it->first << " is too big (" << it->second.blob_size << " bytes), removing it from pool");
+        remove = true;
+      }
+      else if (m_blockchain.have_tx(it->first)) {
+        LOG_PRINT_L1("Transaction " << it->first << " is in the blockchain, removing it from pool");
+        remove = true;
+      }
+      if (remove) {
         remove_transaction_keyimages(it->second.tx);
         auto sorted_it = find_tx_in_sorted_container(it->first);
         if (sorted_it == m_txs_by_fee_and_receive_time.end())