Comment 12 for bug 1609056

Reviewed: https://review.openstack.org/350576
Committed: https://git.openstack.org/cgit/openstack/openstack-ansible-repo_build/commit/?id=ae56b67cc07ca5a1e2dd03c74b5049b5942f41cf
Submitter: Jenkins
Branch: stable/mitaka

commit ae56b67cc07ca5a1e2dd03c74b5049b5942f41cf
Author: Jesse Pretorius <email address hidden>
Date: Wed Aug 3 00:15:56 2016 +0100

    Fix repo constraints construction and package installation

    The current repo build process has the following issues:

    1. The constraints consruction doesn't properly handle two constraints
       which use the same name, but have different version specs. eg:
       ovs===2.5.0;python_version=='2.7'
       ovs===2.6.0.dev2;python_version=='3.4'
       This is a problem in the constraints construction.

    2. The pip packages installed on the repo server in order to
       construct the repo do not respect the global pins or the upper
       constraint overrides.

    3. The constraints are selected based on the requirements specified.
       This makes the process unnecessarily complex.

    4. The global pins are not applied to the constructed constraints,
       so the wrong packages get built and installed.

    This patch corrects all of these issues and hopefully makes the
    mechanism for constructing constraints more readily apparent, and
    therefore easier to maintain.

    Conflicts:
    >------tasks/repo_pre_build.yml
    >------tests/test-repo-build.yml
    >------tests/test-vars.yml

    This backport also includes corrections to the template from
    https://review.openstack.org/350654

    Depends-On: Ic473eb9de26a2a3b92e234851b8f731c0255976c
    Change-Id: If52d073d43081468e2faf2cd063c4b211c29994f
    Related-Bug: #1605846
    Closes-Bug: #1609056
    (cherry picked from commit 38d7faffa96aa2b03e718320f2dc281cc12029b8)