install oslo from upstream in devstack

the libraries that have graduated from oslo incubation need to be
made available in devstack so that projects can develop against
upstream versions of these libraries, and that we can test their
compatibility in the gate.

This should also allow us to force global requirements on all the
projects during installation.

Change-Id: Idf527b16b50eb58564ec74428290cd31424f5de2
Merge "install oslo from upstream in devstack"