Page always sends "This is test data"

[groovecoder]

Steps to reproduce:

1. Go to https://mozilla-services.github.io/WebPushDataTestPage/
2. Click to Register the service worker
3. Click to Get the subscription info
4. Update the value in the data textarea input.
5. Click "Encrypt the data"
6. Scroll down to "Send the message" and click "Send the data" or copy and paste the curl commands

Expected results:
The push message should show with the content entered in the data textarea input.

Actual results:
The push message always shows with "This is test data" no matter what's in the data input.