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
"    \"p2sh-segwit\":\"str\" (string) address of the P2SH script wrapping this witness redeem script.\n"
            "}\n"
                },
                RPCExamples{
                    HelpExampleCli("decodescript", "\"hexstring\"")
            + HelpExampleRpc("decodescript", "\"hexstring\"")
                },
    };
    if (request.fHelp || !help.IsValidNumArgs(request.params.size())) {
        throw std::runtime_error(help.ToString());
    }
    RPCTypeCheck(request.params, {UniValue::VSTR});
    UniValue r(UniValue::VOBJ);
    CScript script;
    if (request.params[0].get_str().size() > 0){
        std::vector<unsigned char> scriptData(ParseHexV(request.params[0], "argument"));
        script = CScript(scriptData.begin(), scriptData.end());
    } else {
        
    }
    ScriptPubKeyToUniv(script, r,  false);
    UniValue type;
    type = find_value(r, "type");
    if (type.isStr() && type.get_str() != "scripthash") {
        
        
        r.pushKV("p2sh", EncodeDestination(CScriptID(script)));
        
        
        if (type.get_str() == "pubkey" || type.get_str() == "pubkeyhash" || type.get_str() == "multisig" || type.get_str() == "nonstandard") {