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)
{
    if (request.fHelp || request.params.size() < 1 || request.params.size() > 2) {
        throw std::runtime_error(
            "getmempooldescendants txid (verbose)\n"
            "\nIf txid is in the mempool, returns all in-mempool descendants.\n"
            "\nArguments:\n"
            "1. \"txid\"                 (string, required) The transaction id (must be in mempool)\n"
            "2. verbose                  (boolean, optional, default=false) True for a json object, false for array of transaction ids\n"
            "\nResult (for verbose=false):\n"
            "[                       (json array of strings)\n"
            "  \"transactionid\"           (string) The transaction id of an in-mempool descendant transaction\n"
            "  ,...\n"
            "]\n"
            "\nResult (for verbose=true):\n"
            "{                           (json object)\n"
            "  \"transactionid\" : {       (json object)\n"
            + EntryDescriptionString()
            + "  }, ...\n"
            "}\n"
            "\nExamples:\n"
            + HelpExampleCli("getmempooldescendants", "\"mytxid\"")
            + HelpExampleRpc("getmempooldescendants", "\"mytxid\"")
            );
    }
    bool fVerbose = false;
    if (!request.params[1].isNull())