Make the py33 Jenkins job happy

This is the first step toward getting Keystone up and running on
Python 3. This patch will create a virtualenv, but will not actually
run any tests. Future patches will enable testing modules as
incompatibilities are worked out.

bp python3

Change-Id: I1ca3bad7ec8789872791a18594cd6f3b4bf911eb
Merge "Make the py33 Jenkins job happy"