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
UniValue entry(UniValue::VOBJ);
            if (involvesWatchonly || (::IsMine(*pwallet, s.destination) & ISMINE_WATCH_ONLY)) {
                entry.pushKV("involvesWatchonly", true);
            }
            MaybePushAddress(entry, s.destination);
            entry.pushKV("category", "send");
            entry.pushKV("amount", ValueFromAmount(-s.amount));
            if (pwallet->mapAddressBook.count(s.destination)) {
                entry.pushKV("label", pwallet->mapAddressBook[s.destination].name);
            }
            entry.pushKV("vout", s.vout);
            entry.pushKV("fee", ValueFromAmount(-nFee));
            if (fLong)
                WalletTxToJSON(pwallet->chain(), locked_chain, wtx, entry);
            entry.pushKV("abandoned", wtx.isAbandoned());
            ret.push_back(entry);
        }
    }
    
    if (listReceived.size() > 0 && wtx.GetDepthInMainChain(locked_chain) >= nMinDepth)
    {
        for (const COutputEntry& r : listReceived)
        {
            std::string label;
            if (pwallet->mapAddressBook.count(r.destination)) {
                label = pwallet->mapAddressBook[r.destination].name;
            }
            if (filter_label && label != *filter_label) {
                continue;
            }