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 
"           \"threshold\": xx,     (numeric) the number of blocks with the version bit set required to activate the feature \n"
            "           \"elapsed\": xx,       (numeric) the number of blocks elapsed since the beginning of the current period \n"
            "           \"count\": xx,         (numeric) the number of blocks with the version bit set in the current period \n"
            "           \"possible\": xx       (boolean) returns false if there are not enough blocks left in this period to pass activation threshold \n"
            "        }\n"
            "     }\n"
            "  }\n"
            "  \"warnings\" : \"...\",           (string) any network and blockchain warnings.\n"
            "}\n"
                },
                RPCExamples{
                    HelpExampleCli("getblockchaininfo", "")
            + HelpExampleRpc("getblockchaininfo", "")
                },
            }.ToString());
    LOCK(cs_main);
    const CBlockIndex* tip = chainActive.Tip();
    UniValue obj(UniValue::VOBJ);
    obj.pushKV("chain",                 Params().NetworkIDString());
    obj.pushKV("blocks",                (int)chainActive.Height());
    obj.pushKV("headers",               pindexBestHeader ? pindexBestHeader->nHeight : -1);
    obj.pushKV("bestblockhash",         tip->GetBlockHash().GetHex());
    obj.pushKV("difficulty",            (double)GetDifficulty(tip));
    obj.pushKV("mediantime",            (int64_t)tip->GetMedianTimePast());
    obj.pushKV("verificationprogress",  GuessVerificationProgress(Params().TxData(), tip));
    obj.pushKV("initialblockdownload",  IsInitialBlockDownload());
    obj.pushKV("chainwork",             tip->nChainWork.GetHex());
    obj.pushKV("size_on_disk",          CalculateCurrentUsage());
    obj.pushKV("pruned",                fPruneMode);
    if (fPruneMode) {