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
+ HelpExampleRpc("getrawtransaction", "\"mytxid\", true")
            + HelpExampleCli("getrawtransaction", "\"mytxid\" false \"myblockhash\"")
            + HelpExampleCli("getrawtransaction", "\"mytxid\" true \"myblockhash\"")
                },
    };
    if (request.fHelp || !help.IsValidNumArgs(request.params.size())) {
        throw std::runtime_error(help.ToString());
    }
    bool in_active_chain = true;
    uint256 hash = ParseHashV(request.params[0], "parameter 1");
    CBlockIndex* blockindex = nullptr;
    if (hash == Params().GenesisBlock().hashMerkleRoot) {
        
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "The genesis block coinbase is not considered an ordinary transaction and cannot be retrieved");
    }
    
    bool fVerbose = false;
    if (!request.params[1].isNull()) {
        fVerbose = request.params[1].isNum() ? (request.params[1].get_int() != 0) : request.params[1].get_bool();
    }
    if (!request.params[2].isNull()) {
        LOCK(cs_main);
        uint256 blockhash = ParseHashV(request.params[2], "parameter 3");
        blockindex = LookupBlockIndex(blockhash);
        if (!blockindex) {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block hash not found");
        }
        in_active_chain = chainActive.Contains(blockindex);
    }
    bool f_txindex_ready = false;