travis log: https://travis-ci.org/bitcoin/bitcoin/jobs/327785286

```
2018-01-11 17:49:08.016000 TestFramework (INFO): Sending from node 1 (['-addresstype=p2sh-segwit']) with multisig using default
2018-01-11 17:49:10.096000 TestFramework (INFO): Sending from node 2 (['-addresstype=p2sh-segwit', '-changetype=bech32']) with multisig using default
2018-01-11 17:49:12.492000 TestFramework (ERROR): Assertion failed
Traceback (most recent call last):
  File "/home/travis/build/bitcoin/bitcoin/build/bitcoin-i686-pc-linux-gnu/test/functional/test_framework/test_framework.py", line 118, in main
    self.run_test()
  File "/home/travis/build/bitcoin/bitcoin/build/bitcoin-i686-pc-linux-gnu/test/functional/address_types.py", line 183, in run_test
    assert_equal(unconf_balances[to_node], to_send * 10 * (2 + n))
  File "/home/travis/build/bitcoin/bitcoin/build/bitcoin-i686-pc-linux-gnu/test/functional/test_framework/util.py", line 38, in assert_equal
    raise AssertionError("not(%s)" % " == ".join(str(arg) for arg in (thing1, thing2) + args))
AssertionError: not(0E-8 == 714.73999460)
#include <policy/feerate.h>
#include <policy/policy.h>
#include <primitives/transaction.h>
#include <rpc/server.h>
#include <streams.h>
#include <sync.h>
#include <txdb.h>
#include <txmempool.h>
#include <util.h>
#include <utilstrencodings.h>
#include <hash.h>
#include <warnings.h>
#include <stdint.h>
#include <univalue.h>
#include <boost/thread/thread.hpp> 
#include <mutex>
#include <condition_variable>
struct CUpdatedBlock
{
    uint256 hash;
    int height;
};
static std::mutex cs_blockchange;
static std::condition_variable cond_blockchange;
static CUpdatedBlock latestblock;
extern void TxToJSON(const CTransaction& tx, const uint256 hashBlock, UniValue& entry);
/* Calculate the difficulty for a given block index,
 * or the block index of the given chain.
 */
double GetDifficulty(const CChain& chain, const CBlockIndex* blockindex)