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
+ HelpExampleCli("listunspent", "6 9999999 '[]' true '{ \"minimumAmount\": 0.005 }'")
            + HelpExampleRpc("listunspent", "6, 9999999, [] , true, { \"minimumAmount\": 0.005 } ")
                },
            }.ToString());
    int nMinDepth = 1;
    if (!request.params[0].isNull()) {
        RPCTypeCheckArgument(request.params[0], UniValue::VNUM);
        nMinDepth = request.params[0].get_int();
    }
    int nMaxDepth = 9999999;
    if (!request.params[1].isNull()) {
        RPCTypeCheckArgument(request.params[1], UniValue::VNUM);
        nMaxDepth = request.params[1].get_int();
    }
    std::set<CTxDestination> destinations;
    if (!request.params[2].isNull()) {
        RPCTypeCheckArgument(request.params[2], UniValue::VARR);
        UniValue inputs = request.params[2].get_array();
        for (unsigned int idx = 0; idx < inputs.size(); idx++) {
            const UniValue& input = inputs[idx];
            CTxDestination dest = DecodeDestination(input.get_str());
            if (!IsValidDestination(dest)) {
                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, std::string("Invalid Bitcoin address: ") + input.get_str());
            }
            if (!destinations.insert(dest).second) {
                throw JSONRPCError(RPC_INVALID_PARAMETER, std::string("Invalid parameter, duplicated address: ") + input.get_str());
            }
        }
    }
    bool include_unsafe = true;