Error in multisig transaction with ledger and local key

Hi,

I am trying to do a multisig p2sh transaction, signing first by ledger and then by locally stored key.

This is my current code mostly based on [Multi Sig guide](https://bcoin.io/guides/multisig-tx.html) and [P2SH ledger example](https://github.com/bcoin-org/bledger/blob/master/examples/bcoin-spendP2SH.js)

Code:

```
'use strict';

const fs = require('fs');
const bcoin = require('bcoin');
const assert = require('assert');
const KeyRing = bcoin.wallet.WalletKey;
const Script = bcoin.Script;
const MTX = bcoin.MTX;
const TX = bcoin.TX;
const Amount = bcoin.Amount;
const Coin = bcoin.Coin;

const bledger = require('../lib/bledger');
const {LedgerBcoin, LedgerTXInput} = bledger;
const {Device} = bledger.USB;

const NETWORK = 'testnet';
const compressed = true;

// Read keys from local system
const secret1 = fs.readFileSync(`./${NETWORK}-key1.wif`).toString();
const ring1 = KeyRing.fromSecret(secret1);

(async () => {

// LEDGER INIT CODE --START
const device = await Device.requestDevice();
device.set({timeout: 50000});
await device.open();
const path = 'm/44\'/0\'/0\'';
const path1 = `${path}/1/1`;
const bcoinApp = new LedgerBcoin({device});
const hdpub1 = await bcoinApp.getPublicKey(path1);
const pub1 = hdpub1.publicKey;
// LEDGER INIT CODE --FINISH

//Create Script
const [pk1, pk2] = [hdpub1.publicKey, ring1.publicKey];
const [m, n] = [2, 2];

const redeem = Script.fromMultisig(m, n, [pk1, pk2]);
// p2sh script
const script = Script.fromScripthash(redeem.hash160());
const changeAddr = script.getAddress().toBase58(NETWORK);

// tx info
const sendTo = '2N4MrGXsu2PtDFMXZrvG34YQxK4Y77bmk7g';
const txInfo = {
// How much we received with this transaction
value: Amount.fromBTC('0.0002').toValue(),

// prevout txid and vout
hash: 'aa253ca490d7f1c914246ad459a89c997291da9ca3dc7ec749f6555d2a5aabdf',
index: 0
};

const coin = Coin.fromJSON({
version: 1,
height: -1,
value: txInfo.value,
coinbase: false,

script: script.toJSON(),
hash: txInfo.hash,
index: txInfo.index
});

// Now we create mutable transaction object for signing with ledger
const spend1 = new MTX();
spend1.script = redeem;

// send
spend1.addOutput({
address: sendTo,
value: Amount.fromBTC('0.0001').toValue()
});

// send change to ourselves
spend1.addOutput({
address: changeAddr,
value: Amount.fromBTC('0.00005').toValue()
});

spend1.addCoin(coin);

const ledgerInputs = [];

// Hex of input transaction
const tx = TX.fromRaw(Buffer.from("01000000000101cdede91d7a739ba4100a46d3287fc20fa683720a39ca2b6e8f474a24570ab86a000000001716001409785e5b583363e2cfcff123be008fef302bd151ffffffff023cf30e000000000017a91470329ef305289ecfe4f2bc6448a6bac4b16b99b887204e00000000000017a9149fd0d66463fafe0ce272189faa4d196ab816ccf787024830450221008a727b5cf7d1f66f1cb3a3311937827a10818d6f8fd6320ebd55df7c5a6d0755022066a4a2f236f01ec6827e7627e5381f1f5ffee56b404d81b44d14ab86b593141d012102e054e792bf5c8e49d2ad73c60a2882e4a34f42db79b0981f95062718dff95a0b00000000", 'hex'))

const ledgerInput = new LedgerTXInput({
tx: tx,
index: 0,
redeem: redeem,
path: path,
publicKey: pub1
});

ledgerInputs.push(ledgerInput);

await bcoinApp.signTransaction(spend1, ledgerInputs);

//Get raw txn signed by ledger
const raw = spend1.toRaw();

// use raw tx to be signed by local key
const spend2 = MTX.fromRaw(raw);
spend2.script = redeem;

// Because input already exists in transaction
// we only need to provide Coin to CoinView
spend2.view.addCoin(coin);

// now we sign
spend2.signInput(0, coin, ring1);

//Check if transaction is valid
assert(spend2.verify(), 'Transaction isnt valid.');

console.log(spend2.toRaw().toString('hex'));

await device.close();
})().catch((e) => {
console.error(e);
process.exit(1);
});
```

Currently, It's throwing me following error:
```
Error: Could not template input.
at LedgerBcoin.applySignature (/ledger/bcoin/bledger/lib/ledger/ledgerbcoin.js:370:13)
at LedgerBcoin._signTransaction (/ledger/bcoin/bledger/lib/ledger/ledgerbcoin.js:340:19)
```

Any pointers on what I am doing wrong?