Do not append commit hash to version (facebookresearch#4472)

Summary:
# Before submitting

- [ ] Was this discussed/approved via a Github issue? (no need for typos, doc improvements)
- [ ] Did you read the [contributor guideline](https://github.com/pytorch/fairseq/blob/main/CONTRIBUTING.md)?
- [ ] Did you make sure to update the docs?
- [ ] Did you write any new necessary tests?

## What does this PR do?
Fixes # (issue).

## PR review
Anyone in the community is free to review the PR once the tests have passed.
If we didn't discuss your PR in Github issues there's a high chance it will not be merged.

## Did you have fun?
Make sure you had fun coding �

Pull Request resolved: facebookresearch#4472

Reviewed By: cbalioglu

Differential Revision: D37047097

Pulled By: dianaml0

fbshipit-source-id: 7cc67bb6661a393d7e5d15f1be7d35646cef5181

setup.py

@@ -18,17 +18,6 @@ def write_version_py():
     with open(os.path.join("fairseq", "version.txt")) as f:
         version = f.read().strip()
 
-    # append latest commit hash to version string
-    try:
-        sha = (
-            subprocess.check_output(["git", "rev-parse", "HEAD"])
-            .decode("ascii")
-            .strip()
-        )
-        version += "+" + sha[:7]
-    except Exception:
-        pass
-
     # write version info to fairseq/version.py
     with open(os.path.join("fairseq", "version.py"), "w") as f:
         f.write('__version__ = "{}"\n'.format(version))