Cannot specify babel path in stealconfig

How often can you reproduce it?

Description:

If you have a code-base that needs a specific version of Babel you can include it using paths config.

I have tried doing so for both npm config and stealconfig.js approaches.

Looks like this line is the culprit https://github.com/stealjs/steal/blob/master/steal.js#L6889 as replacing with the following results in the paths override working correctly:

setIfNotPresent(this.paths,"babel", dirname+"/ext/babel.js");

Steps to reproduce:

npm install -S steal@2 babel-standalone
Configure paths as per https://stealjs.com/docs/StealJS.babel.html#specifying-version
Create and load an ES module so it is transpiled (and therefore Babel is loaded)

{
  "steal": {
    "paths": {
      "babel": "node_modules/babel-standalone/babel.js"
    }
  }
}

Expected results:

Babel is loaded from node_modules/babel-standalone/babel.js.

Actual results:

Babel is loaded from node_modules/steal/ext/babel.js.

Environment:

stealjs / steal