Updated openstack/openstack
Project: openstack/oslo.vmware  c6f6ba9fd9226f5e238ba3f8a7672fd006924639

Add pbr to installation requirements

Add pbr to the list of installation requirements so that it is installed
via pip before this library is installed, instead of with easy_install.
This avoids issues like Bug #1384919, and ensures that projects that use
this library as a dependency are properly installed.

Change-Id: I6c155370dbd01fe4748d5137bdf288e8d3e1a67e