Provide visual feedback on unsuccessful update attempts

Edit Subject

Ghostery 2.6.0.1 for Firefox fails silently if XMLHttpRequest returns an HTTP status other than 200. In that case, I recommend displaying an alert containing the statusText.

In the future, administratively-disabled updates should be indicated with something besides 404: I would probably go with 503, but I could also envision a scenario in which 204 might be used.

Affects: chrome://ghostery/content/ghostery-db.js

Reference:

• https://developer.mozilla.org/en/DOM/...