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 
mutable size_t vTxHashesIdx; 
};
struct update_descendant_state
{
    update_descendant_state(int64_t _modifySize, CAmount _modifyFee, int64_t _modifyCount) :
        modifySize(_modifySize), modifyFee(_modifyFee), modifyCount(_modifyCount)
    {}
    void operator() (CTxMemPoolEntry &e)
        { e.UpdateDescendantState(modifySize, modifyFee, modifyCount); }
    private:
        int64_t modifySize;
        CAmount modifyFee;
        int64_t modifyCount;
};
struct update_ancestor_state
{
    update_ancestor_state(int64_t _modifySize, CAmount _modifyFee, int64_t _modifyCount, int64_t _modifySigOpsCost) :
        modifySize(_modifySize), modifyFee(_modifyFee), modifyCount(_modifyCount), modifySigOpsCost(_modifySigOpsCost)
    {}
    void operator() (CTxMemPoolEntry &e)
        { e.UpdateAncestorState(modifySize, modifyFee, modifyCount, modifySigOpsCost); }
    private:
        int64_t modifySize;
        CAmount modifyFee;
        int64_t modifyCount;
        int64_t modifySigOpsCost;
};
struct update_fee_delta
{
    explicit update_fee_delta(int64_t _feeDelta) : feeDelta(_feeDelta) { }