Desktop notification should show Pipeline not Job

Desktop notification should show Pipeline not Job

---

See

• "should it say Pipeline instead of job?", https://gitlab.slack.com/archives/frontend/p1486661800014905,
  • "Yeah, Pipeline", https://gitlab.slack.com/archives/frontend/p1486663136014918
• https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8787