Comment 4 for bug 1294381

I think 84081 fixes this as a side effect or pip being a transitive dependency for projects (pbr depends on it). The explicit installs of pip, virtualenv, wheel and friends does not use the pip command, they use the upgrade command. We should make sure that the explicit installs of pip and friends do the correct thing instead of relying on the convenient but potentially unreliable behavior 84041 exploits.

Not only that but we don't actually want to reinstall every package. Mirror builds are much quicker the second time around because it takes advantage of precached packages. If we must reinstall pip and friends we should only reinstall pip and friends and not the others.