Thanks to lifeless, pip now implicitly has a wheel cache so that it
builds a wheel before every install, and uses that cache. All our
clever attempts at manually doing wheelhouse things is actually
bypassing the existing cache and making things take longer.
We should remove all of this code and just let pip do this thing,
which is does very well, and get out of the way.
Change-Id: Ia140dc34638d893b92f66d1ba20efd9522c5923b
(cherry picked from commit 9013bb0c24)
b30dca9a30