Always store git sha in _version.py during installation

[bryceml]

What does this PR do?

It always puts the git sha in salt/_version.py when it's generating it's version automatically.

The main difference that tagged versions will include the git sha in that file so it can be figured out later what exact sha is being run, I don't think there should be any other changes anywhere.

What issues does this PR fix or reference?

Previous Behavior

tagged versions did not store the git sha

New Behavior

tagged versions also store the git sha

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltstack.com/en/master/topics/development/changelog.html
• Tests written/updated

[Ch3LL]

What's the use case where you would need the sha? I would assume when you tag a version you only want the tag version not the sha included

[bryceml]

It doesn't show up graphically anywhere, or in any output. It's mainly so when we do the nightly builds, you can track down the exact sha it came from.

For the non-tiamat packages, you can't have a - in the version in the egg info of the python package or rpmbuild errors out. So I'm doing what we've done in the past with something like 3002.2nb[some number]