Rally does not adhere to the global requirements process, so its
requirements extend beyond those managed by upper-constraints, and
sometimes are incompatible with upper constraints.
We have no need to track their development from git commit to git
commit, and can rather rely on stable releases which we verify are
working with the upper constraints whenever we do a pinning bump.
This keeps things simpler for us, and also allows the repo build
process in the integrated build to do a constrained venv build
instead of doing it unconstrained and breaking stable branch builds
down the line.
Depends-On: https://review.openstack.org/570906
Change-Id: If3d0120cf6f6f78463cf7805bc046382c3b6d44e
321fb7e69a