[stable-only] Cap virtualenv for py37stable/train

py37 test started to fail with latest virtualenv (20.16.4) as it
bundles setuptools 65.3.0, which causes installation problems under
py37. (Note: with py38 the problem does not occur).

This patch sets virtualenv<20.16.4 to unblock the gate as
virtualenv 20.16.3 bundles setuptools 63.4.1, with which py37 gate
works well.

NOTE(stephenfin): Modified to remove the failing l-c job.

Conflicts:
  .zuul.yaml
  tox.ini

NOTE(elod.illes): conflict in .zuul.yaml is caused by ussuri job
  template changes; conflict in tox.ini is caused by cleanup patch
  I2ab1eb99a61695bfbc7ecc66f215b1cb991007dd.

Change-Id: I8c457d06b79cacc770db62eac1d8e4459052d5ba
(cherry picked from commit 95ac6392a0dbfd816f6300c860a8d8dd2e04bdd3)

2 files changed, 4 insertions, 1 deletions

diff --git a/.zuul.yaml b/.zuul.yaml
index 9bb6ef1..4f0c560 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -4,7 +4,6 @@
       - lib-forward-testing
       - lib-forward-testing-python3
       - openstack-cover-jobs
-      - openstack-lower-constraints-jobs
       - openstack-python-jobs
       - openstack-python3-train-jobs
       - periodic-stable-jobs
diff --git a/tox.ini b/tox.ini
index 4abd8bc..627478a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,10 @@
 [tox]
 minversion = 2.0
 envlist = py27,py37,pep8
+# Pin setuptools via virtualenv as latest virtualenv pulls in 65.3.0
+# version of setuptools for py37, which causes installation problems
+# (virtualenv 20.16.3 uses setuptools 63.4.1).
+requires = virtualenv<20.16.4
 
 [testenv]
 install_command = pip install {opts} {packages}