Remove useless code

[mszhanyi]

Since we're using specific VS, we don't need to specify VC version.
In fact, the VC version is not used in CI now.

Why I make this change now?
I'm writing a robot to update the vs_install.ps1 (#56261) every 2 weeks.
It will submit a PR to check if the latest VS is compatible with PyTorch automatically.

[facebook-github-bot]

💊 CI failures summary and remediations

As of commit c5303f8 (more details on the Dr. CI page):

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• 2/2 failures introduced in this PR

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🕵️ 2 new failures recognized by patterns

The following CI failures do not appear to be due to upstream breakages:

pytorch_linux_xenial_py3_6_gcc5_4_build (1/2)

Step: "(Optional) Merge target branch" (full log | diagnosis details | 🔁 rerun)

Automatic merge failed; fix conflicts and then commit the result.

CONFLICT (add/add): Merge conflict in .github/workflows/auto_label.yml
Auto-merging .github/workflows/auto_label.yml
CONFLICT (add/add): Merge conflict in .github/workflows/add_annotations.yml
Auto-merging .github/workflows/add_annotations.yml
CONFLICT (add/add): Merge conflict in .circleci/verbatim-sources/job-specs/pytorch-job-specs.yml
Auto-merging .circleci/verbatim-sources/job-specs/pytorch-job-specs.yml
CONFLICT (add/add): Merge conflict in .circleci/config.yml
Auto-merging .circleci/config.yml
CONFLICT (add/add): Merge conflict in .circleci/cimodel/data/windows_build_definitions.py
Auto-merging .circleci/cimodel/data/windows_build_definitions.py
Automatic merge failed; fix conflicts and then commit the result.


Exited with code exit status 1

pytorch_xla_linux_bionic_py3_6_clang9_build (2/2)

Step: "(Optional) Merge target branch" (full log | diagnosis details | 🔁 rerun)

Automatic merge failed; fix conflicts and then commit the result.

CONFLICT (add/add): Merge conflict in .github/workflows/auto_label.yml
Auto-merging .github/workflows/auto_label.yml
CONFLICT (add/add): Merge conflict in .github/workflows/add_annotations.yml
Auto-merging .github/workflows/add_annotations.yml
CONFLICT (add/add): Merge conflict in .circleci/verbatim-sources/job-specs/pytorch-job-specs.yml
Auto-merging .circleci/verbatim-sources/job-specs/pytorch-job-specs.yml
CONFLICT (add/add): Merge conflict in .circleci/config.yml
Auto-merging .circleci/config.yml
CONFLICT (add/add): Merge conflict in .circleci/cimodel/data/windows_build_definitions.py
Auto-merging .circleci/cimodel/data/windows_build_definitions.py
Automatic merge failed; fix conflicts and then commit the result.


Exited with code exit status 1

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[peterjc123]

I'm fine with this PR. But what about our users? Do you expect them to downgrade VS as well? Since most issues are caused by the upgrade of STL, maybe making it a submodule of PyTorch seems a good idea. What do you think, @malfet @ezyang ?

[ezyang]

I think it's reasonable to say that most average Windows users will just be incapable of building PyTorch from source and will use our binaries. Requiring a specific MSVC version (and saying you get the keep the pieces if you try another one) seems reasonable.

[facebook-github-bot]

@ezyang has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@ezyang merged this pull request in a14178e.