Replace removed constants with overridable methods

[dduugg]

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We should avoid remove_const, especially when redefining the removed const, as it violates normal assumptions of a "constant".

Surprisingly, there's no cop to disallow this method, except for the narrow case of specs. (There is an open issue for a general DisallowedMethods cop, which has some code snippets, should we want to bother with a custom rule.)

[dduugg]

Needs to be merged in sync with Homebrew/homebrew-test-bot#1257 (or, on request, I can update the PR to dual-support constants and methods as an intermediate step.)

[MikeMcQuaid]

Makes sense to me! Keg::MUST_BE_WRITABLE_DIRECTORIES is used in brew test-bot so should stick around until it's fixed there first.

[MikeMcQuaid]

or, on request, I can update the PR to dual-support constants and methods as an intermediate step.)

Yes, intermediate step will be necessary to get this merged 👍🏻

[dduugg]

Updated PR to maintain dual support until Homebrew/homebrew-test-bot#1257 goes in