Fix installing taps in brew install.

[reitermarkus]

Partially reverts f54b458.

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew tests with your changes locally?
• Have you successfully run brew man locally and committed any changes?

---

Re-add previous tapping logic.

Closes #8830.

[MikeMcQuaid]

Thanks for this ❤️