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::vector<std::vector<unsigned char>> solutions_data;
            txnouttype which_type = Solver(script, solutions_data);
            
            
            if ((which_type == TX_PUBKEY) || (which_type == TX_MULTISIG)) {
                for (const auto& solution : solutions_data) {
                    if ((solution.size() != 1) && !CPubKey(solution).IsCompressed()) {
                        return r;
                    }
                }
            }
            UniValue sr(UniValue::VOBJ);
            CScript segwitScr;
            if (which_type == TX_PUBKEY) {
                segwitScr = GetScriptForDestination(WitnessV0KeyHash(Hash160(solutions_data[0].begin(), solutions_data[0].end())));
            } else if (which_type == TX_PUBKEYHASH) {
                segwitScr = GetScriptForDestination(WitnessV0KeyHash(solutions_data[0]));
            } else {
                
                
                segwitScr = GetScriptForDestination(WitnessV0ScriptHash(script));
            }
            ScriptPubKeyToUniv(segwitScr, sr,  true);
            sr.pushKV("p2sh-segwit", EncodeDestination(CScriptID(segwitScr)));
            r.pushKV("segwit", sr);
        }
    }
    return r;
}
static UniValue combinerawtransaction(const JSONRPCRequest& request)