Revert "Remove extra parse-time dependencies."

This reverts commit 117de052fb5cefbae77e3c4151b1dc89b9e89593.
Make salt.version not depend on the rest of salt.

Fix to let pip install salt with all dependencies.
Emulate check_output for Python 2.6 support.
Merge pull request #3360 from YorikSar/depend-fix

Remove extra parse-time dependencies [2nd round].