Revert "always use sitepackages"

This reverts commit c81568fa85620746534331cd820b0bb399719149.

After learning what I learned about how sitepackages works, this
wasn't really a sane change. Revert back to old behavior.

Change-Id: I8079a0f4d9e0bc2e51a743d4f23cf98d4840a3ab
Merge "Revert "always use sitepackages""