travis run: https://travis-ci.org/bitcoin/bitcoin/jobs/406813397

```
rpc_psbt.py failed, Duration: 4 s
stdout:
2018-07-22T13:28:57.765000Z TestFramework (INFO): Initializing test directory /tmp/bitcoin_test_runner_20180722_132530/rpc_psbt_49
2018-07-22T13:29:00.531000Z TestFramework (ERROR): Assertion failed
Traceback (most recent call last):
  File "/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/test/functional/test_framework/test_framework.py", line 160, in main
    self.run_test()
  File "/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/test/functional/rpc_psbt.py", line 101, in run_test
    assert_raises_rpc_error(-22, "TX decode failed", self.nodes[0].converttopsbt, signedtx['hex'])
  File "/home/travis/build/bitcoin/bitcoin/build/bitcoin-x86_64-unknown-linux-gnu/test/functional/test_framework/util.py", line 105, in assert_raises_rpc_error
    assert try_rpc(code, message, fun, *args, **kwds), "No exception raised"
AssertionError: No exception raised
{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() > 5)
        throw std::runtime_error(
            RPCHelpMan{"listunspent",
                "\nReturns array of unspent transaction outputs\n"
                "with between minconf and maxconf (inclusive) confirmations.\n"
                "Optionally filter to only include txouts paid to specified addresses.\n",
                {
                    {"minconf", RPCArg::Type::NUM,  "1", "The minimum confirmations to filter"},
                    {"maxconf", RPCArg::Type::NUM,  "9999999", "The maximum confirmations to filter"},
                    {"addresses", RPCArg::Type::ARR,  "empty array", "A json array of bitcoin addresses to filter",
                        {
                            {"address", RPCArg::Type::STR, RPCArg::Optional::OMITTED, "bitcoin address"},
                        },
                    },
                    {"include_unsafe", RPCArg::Type::BOOL,  "true", "Include outputs that are not safe to spend\n"
            "                  See description of \"safe\" attribute below."},
                    {"query_options", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED_NAMED_ARG, "JSON with query options",
                        {
                            {"minimumAmount", RPCArg::Type::AMOUNT,  "0", "Minimum value of each UTXO in " + CURRENCY_UNIT + ""},
                            {"maximumAmount", RPCArg::Type::AMOUNT,  "unlimited", "Maximum value of each UTXO in " + CURRENCY_UNIT + ""},
                            {"maximumCount", RPCArg::Type::NUM,  "unlimited", "Maximum number of UTXOs"},