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 
return TxMempoolInfo{it->GetSharedTx(), it->GetTime(), CFeeRate(it->GetFee(), it->GetTxSize()), it->GetModifiedFee() - it->GetFee()};
}
std::vector<TxMempoolInfo> CTxMemPool::infoAll() const
{
    LOCK(cs);
    auto iters = GetSortedDepthAndScore();
    std::vector<TxMempoolInfo> ret;
    ret.reserve(mapTx.size());
    for (auto it : iters) {
        ret.push_back(GetInfo(it));
    }
    return ret;
}
CTransactionRef CTxMemPool::get(const uint256& hash) const
{
    LOCK(cs);
    indexed_transaction_set::const_iterator i = mapTx.find(hash);
    if (i == mapTx.end())
        return nullptr;
    return i->GetSharedTx();
}
TxMempoolInfo CTxMemPool::info(const uint256& hash) const
{
    LOCK(cs);
    indexed_transaction_set::const_iterator i = mapTx.find(hash);
    if (i == mapTx.end())
        return TxMempoolInfo();
    return GetInfo(i);
}
void CTxMemPool::PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta)