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 
extern CAmount maxTxFee;
extern int64_t nMaxTipAge;
extern bool fEnableReplacement;
extern uint256 hashAssumeValid;
extern arith_uint256 nMinimumChainWork;
extern CBlockIndex *pindexBestHeader;
extern bool fHavePruned;
extern bool fPruneMode;
extern uint64_t nPruneTarget;
static const unsigned int MIN_BLOCKS_TO_KEEP = 288;
static const unsigned int NODE_NETWORK_LIMITED_MIN_BLOCKS = 288;
static const signed int DEFAULT_CHECKBLOCKS = 6;
static const unsigned int DEFAULT_CHECKLEVEL = 3;
static const uint64_t MIN_DISK_SPACE_FOR_BLOCK_FILES = 550 * 1024 * 1024;
/**
 * Process an incoming block. This only returns after the best known valid
 * block is made active. Note that it does not, however, guarantee that the
 * specific block passed to it has been checked for validity!
 *
 * If you want to *possibly* get feedback on whether pblock is valid, you must
 * install a CValidationInterface (see validationinterface.h) - this will have
 * its BlockChecked method called whenever *any* block completes validation.
 *
 * Note that we guarantee that either the proof-of-work is valid on pblock, or
 * (and possibly also) BlockChecked will have been called.
 *
 * May not be called in a
 * validationinterface callback.
 *
 * @param[in]   pblock  The block we want to process.