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)
CUpdatedBlock block;
    {
        std::unique_lock<std::mutex> lock(cs_blockchange);
        if(timeout)
            cond_blockchange.wait_for(lock, std::chrono::milliseconds(timeout), [&height]{return latestblock.height >= height || !IsRPCRunning();});
        else
            cond_blockchange.wait(lock, [&height]{return latestblock.height >= height || !IsRPCRunning(); });
        block = latestblock;
    }
    UniValue ret(UniValue::VOBJ);
    ret.push_back(Pair("hash", block.hash.GetHex()));
    ret.push_back(Pair("height", block.height));
    return ret;
}
UniValue getdifficulty(const JSONRPCRequest& request)
{
    if (request.fHelp || request.params.size() != 0)
        throw std::runtime_error(
            "getdifficulty\n"
            "\nReturns the proof-of-work difficulty as a multiple of the minimum difficulty.\n"
            "\nResult:\n"
            "n.nnn       (numeric) the proof-of-work difficulty as a multiple of the minimum difficulty.\n"
            "\nExamples:\n"
            + HelpExampleCli("getdifficulty", "")
            + HelpExampleRpc("getdifficulty", "")
        );
    LOCK(cs_main);
    return GetDifficulty();
}
std::string EntryDescriptionString()