Reported here: https://github.com/bitcoin/bitcoin/pull/10244#issuecomment-378035305

Travis log here: https://travis-ci.org/bitcoin/bitcoin/jobs/361243719#L2810

Note the JSON exception:

```
test_framework.authproxy.JSONRPCException: The mempool was not loaded yet (-1) 
```

That exception was introduced here: https://github.com/bitcoin/bitcoin/commit/cb1e319fe9e198c9c5cf5236fe9af5a3d748b9e8#diff-a0c8f511d90e83aa9b5857e819ced344R1617

cc @jtimon 
{
    
    LOCK(cs);
    setEntries txToRemove;
    for (indexed_transaction_set::const_iterator it = mapTx.begin(); it != mapTx.end(); it++) {
        const CTransaction& tx = it->GetTx();
        LockPoints lp = it->GetLockPoints();
        bool validLP =  TestLockPointValidity(&lp);
        if (!CheckFinalTx(tx, flags) || !CheckSequenceLocks(*this, tx, flags, &lp, validLP)) {
            
            
            txToRemove.insert(it);
        } else if (it->GetSpendsCoinbase()) {
            for (const CTxIn& txin : tx.vin) {
                indexed_transaction_set::const_iterator it2 = mapTx.find(txin.prevout.hash);
                if (it2 != mapTx.end())
                    continue;
                const Coin &coin = pcoins->AccessCoin(txin.prevout);
                if (nCheckFrequency != 0) assert(!coin.IsSpent());
                if (coin.IsSpent() || (coin.IsCoinBase() && ((signed long)nMemPoolHeight) - coin.nHeight < COINBASE_MATURITY)) {
                    txToRemove.insert(it);
                    break;
                }
            }
        }