Recent updates to openstack upper-constraints.txt for stable/train
moved to updated module versions without python-2.7 support. This
update locks down the stable-wheels.cfg to include the versions of
each upstream python module used in the final stx-3.0 image build,
using the piplst files to determine installed content:
http://mirror.starlingx.cengn.ca/mirror/starlingx/release/3.0.0/centos/outputs/docker-images/
Change-Id: Ice46d9dcc679a48afe3d4d1179c2820aada3136a
Closes-Bug: 1887178
Signed-off-by: Don Penney <don.penney@windriver.com>