formula: remove setting up home for python 2.7

[cho-m]

• 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 typecheck with your changes locally?
• Have you successfully run brew tests with your changes locally?

---

I don't think we need this in homebrew/core where we removed Python 2 usage and none of our runners have Python 2. We even have some workarounds to delete this path in a couple formula tests (e.g. git-annex).

May need some input if there is any use for external taps (in which case I can keep around in unless @tap.core_tap?) or source-builds (in which case maybe some other restriction)

[MikeMcQuaid]

Good spot, makes sense to me, thanks again @cho-m!