Error Upgrading From 1.0.3 -> 2x

Hi there -

I upgraded from 1.0.3 -> 2.0 (with `ember-cli-babel` `7.11.0`) and get this error:

```
Build Error (broccoli-persistent-filter:TransformAmd) in output/chunk1.js

ember-cli-babel-polyfills: unable to remap: chunk1.js
```

Not exactly if this is a problem just with this specific app or elsewhere or I'm missing something else.

Here's the full stack trace:

```
- stack: Error: ember-cli-babel-polyfills: unable to remap: chunk1.js
at TransformAmd.processString (/Users/djwasserman/projects/groundswell/frontend/node_modules/ember-cli-babel-polyfills/lib/transform-amd.js:25:13)
at resolve (/Users/djwasserman/projects/groundswell/frontend/node_modules/ember-cli-babel-polyfills/node_modules/broccoli-persistent-filter/lib/strategies/default.js:10:19)
at initializePromise (/Users/djwasserman/projects/groundswell/frontend/node_modules/rsvp/dist/rsvp.js:520:5)
at new Promise (/Users/djwasserman/projects/groundswell/frontend/node_modules/rsvp/dist/rsvp.js:995:33)
at Object.processString (/Users/djwasserman/projects/groundswell/frontend/node_modules/ember-cli-babel-polyfills/node_modules/broccoli-persistent-filter/lib/strategies/default.js:9:18)
at Processor.processString (/Users/djwasserman/projects/groundswell/frontend/node_modules/ember-cli-babel-polyfills/node_modules/broccoli-persistent-filter/lib/processor.js:19:27)
at resolve (/Users/djwasserman/projects/groundswell/frontend/node_modules/ember-cli-babel-polyfills/node_modules/broccoli-persistent-filter/index.js:353:16)
at initializePromise (/Users/djwasserman/projects/groundswell/frontend/node_modules/rsvp/dist/rsvp.js:520:5)
at new Promise (/Users/djwasserman/projects/groundswell/frontend/node_modules/rsvp/dist/rsvp.js:995:33)
at invoke (/Users/djwasserman/projects/groundswell/frontend/node_modules/ember-cli-babel-polyfills/node_modules/broccoli-persistent-filter/index.js:352:10)
at TransformAmd.Filter.processFile (/Users/djwasserman/projects/groundswell/frontend/node_modules/ember-cli-babel-polyfills/node_modules/broccoli-persistent-filter/index.js:371:16)
at Promise.resolve.then (/Users/djwasserman/projects/groundswell/frontend/node_modules/ember-cli-babel-polyfills/node_modules/broccoli-persistent-filter/index.js:337:21)
at tryCatcher (/Users/djwasserman/projects/groundswell/frontend/node_modules/rsvp/dist/rsvp.js:323:19)
at invokeCallback (/Users/djwasserman/projects/groundswell/frontend/node_modules/rsvp/dist/rsvp.js:495:31)
at /Users/djwasserman/projects/groundswell/frontend/node_modules/rsvp/dist/rsvp.js:559:14
at flush (/Users/djwasserman/projects/groundswell/frontend/node_modules/rsvp/dist/rsvp.js:2402:5)
at process._tickCallback (internal/process/next_tick.js:61:11)
```