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
{
    const RPCHelpMan help{
                "getrawtransaction",
                "\nReturn the raw transaction data.\n"
                "\nBy default this function only works for mempool transactions. When called with a blockhash\n"
                "argument, getrawtransaction will return the transaction if the specified block is available and\n"
                "the transaction is found in that block. When called without a blockhash argument, getrawtransaction\n"
                "will return the transaction if it is in the mempool, or if -txindex is enabled and the transaction\n"
                "is in a block in the blockchain.\n"
                "\nHint: Use gettransaction for wallet transactions.\n"
                "\nIf verbose is 'true', returns an Object with information about 'txid'.\n"
                "If verbose is 'false' or omitted, returns a string that is serialized, hex-encoded data for 'txid'.\n",