Ensure that role tests pin pip/setuptools/wheel

Currently the role tests use whatever versions of pip,
setuptools and wheel are already installed on the host.

When a version of these tools changes it often causes
problems for our testing.

This will ensure that we use a known good set of pins
which is maintained in the general SHA bumping process.

Change-Id: I5720eb69cfbbe24136ebdfcac9c68893b3595b27

test-vars.yml

@@ -462,7 +462,7 @@ swift_proxy_server_workers: 2
 pip_install_options: "--no-binary libvirt-python"
 
 # The URL/path of a constraints file to use when installing the additional pip packages.
-pip_install_upper_constraints: "http://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt"
+pip_install_upper_constraints: "http://git.openstack.org/cgit/openstack/openstack-ansible/plain/global-requirement-pins.txt --constraint http://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt"
 
 # Overriding the developer_constraints allows us to install from local disk as a precedence
 # if the repo is present.

tox.ini

@@ -82,6 +82,7 @@ commands =
 [testenv:ansible]
 deps =
     {[testenv]deps}
+    -rhttps://git.openstack.org/cgit/openstack/openstack-ansible/plain/global-requirement-pins.txt
     -r{toxinidir}/test-ansible-deps.txt