Resolve "Prometheus integration fails on k8s 1.10"

What does this MR do?

From https://gitlab.com/gitlab-org/gitlab-ce/issues/46259#note_74228833

I think we need to monkey patch this, because as of today 1.10 is now GA on GKE: https://cloudplatform.googleblog.com/2018/05/Google-Kubernetes-Engine-1-10-is-generally-available-and-ready-for-the-enterprise.html

The upstream PR I created hasn't been merged yet (discussing documentation at the moment and supported versions), and we'd then need to wait for a release to be cut.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Conform by the code review guidelines
  • Has been reviewed by a UX Designer
  • Has been reviewed by a Frontend maintainer
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Conform by the merge request performance guides
• Conform by the style guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Closes #46259 (closed)