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 
status = "headers-only";
        } else if (block->IsValid(BLOCK_VALID_SCRIPTS)) {
            
            status = "valid-fork";
        } else if (block->IsValid(BLOCK_VALID_TREE)) {
            
            status = "valid-headers";
        } else {
            
            status = "unknown";
        }
        obj.pushKV("status", status);
        res.push_back(obj);
    }
    return res;
}
UniValue MempoolInfoToJSON(const CTxMemPool& pool)
{
    UniValue ret(UniValue::VOBJ);
    ret.pushKV("loaded", g_is_mempool_loaded);
    ret.pushKV("size", (int64_t)pool.size());
    ret.pushKV("bytes", (int64_t)pool.GetTotalTxSize());
    ret.pushKV("usage", (int64_t)pool.DynamicMemoryUsage());
    size_t maxmempool = gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
    ret.pushKV("maxmempool", (int64_t) maxmempool);
    ret.pushKV("mempoolminfee", ValueFromAmount(std::max(pool.GetMinFee(maxmempool), ::minRelayTxFee).GetFeePerK()));
    ret.pushKV("minrelaytxfee", ValueFromAmount(::minRelayTxFee.GetFeePerK()));
    return ret;
}
static UniValue getmempoolinfo(const JSONRPCRequest& request)