message: refactor(core): deprecate hdPath in src/travelRule.ts
  Also remove `self` rebinding.
  The fact that there is a `this.bitgo.decrypt` call further down makes
  me doubt this was ever called.
  Issue:
diff: @@ -16,7 +16,8 @@ import * as Bluebird from 'bluebird';
  import * as _ from 'lodash';
  import * as common from './common';
  -import { getNetwork, makeRandomKey, hdPath } from './bitcoin';
  +import { getNetwork, makeRandomKey } from './bitcoin';
  +import { sanitizeLegacyPath } from './bip32path';
  interface DecryptReceivedTravelRuleOptions {
  tx?: {
  @@ -139,11 +140,9 @@ TravelRule.prototype.decryptReceivedTravelInfo = function (params: DecryptReceiv
  hdNode = bitcoin.HDNode.fromBase58(keychain.xprv);
  }
  - const self = this;
  - const hdPathNode = hdPath(hdNode);
  - tx.receivedTravelInfo.forEach(function (info) {
  - const key = hdPathNode.deriveKey(info.toPubKeyPath);
  - const secret = self.bitgo.getECDHSecret({
  + tx.receivedTravelInfo.forEach((info) => {
  + const key = hdNode.deriveKey(sanitizeLegacyPath(info.toPubKeyPath)).keyPair;
  + const secret = this.bitgo.getECDHSecret({
  eckey: key,
  otherPubKeyHex: info.fromPubKey,
  });
  