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 
void ClearPrioritisation(const uint256 hash);
    
    const CTransaction* GetConflictTx(const COutPoint& prevout) const EXCLUSIVE_LOCKS_REQUIRED(cs);
    
    boost::optional<txiter> GetIter(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs);
    
    setEntries GetIterSet(const std::set<uint256>& hashes) const EXCLUSIVE_LOCKS_REQUIRED(cs);
    /** Remove a set of transactions from the mempool.
     *  If a transaction is in this set, then all in-mempool descendants must
     *  also be in the set, unless this transaction is being removed for being
     *  in a block.
     *  Set updateDescendants to true when removing a tx that was in a block, so
     *  that any in-mempool descendants have their ancestor state updated.
     */
    void RemoveStaged(setEntries &stage, bool updateDescendants, MemPoolRemovalReason reason = MemPoolRemovalReason::UNKNOWN) EXCLUSIVE_LOCKS_REQUIRED(cs);
    /** When adding transactions from a disconnected block back to the mempool,
     *  new mempool entries may have children in the mempool (which is generally
     *  not the case when otherwise adding transactions).
     *  UpdateTransactionsFromBlock() will find child transactions and update the
     *  descendant state for each transaction in vHashesToUpdate (excluding any
     *  child transactions present in vHashesToUpdate, which are already accounted
     *  for).  Note: vHashesToUpdate should be the set of transactions from the
     *  disconnected block that have been accepted back into the mempool.
     */
    void UpdateTransactionsFromBlock(const std::vector<uint256>& vHashesToUpdate) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    /** Try to calculate all in-mempool ancestors of entry.
     *  (these are all calculated including the tx itself)
     *  limitAncestorCount = max number of ancestors
     *  limitAncestorSize = max size of ancestors
     *  limitDescendantCount = max number of descendants any ancestor can have