This reverts commit ab89c7d69c.
This commit checked for DIB_PYTHON_VERSION and only installed the v3
packages. This is unfortunately backwards-incompatible, as consumers
such as the openstack gate are relying on this package installing pip
& virtualenv packages for python2 AND python3.
This was sort-of expressed in the docs, where it discusses what the
resulting setup of the system will be, but I've added a note to make
it clearer.
If we want to change this, I think we'll need either a new element, or
a non-defaulting flag.
Change-Id: I419dbdf4682394db68974944af1e5c432f3e0565