Use templates for cover and lower-constraints

Use openstack-tox-cover template, this runs the cover job as
non-voting in the check queue only.

Use openstack-lower-constraints-jobs template

Remove jobs that are part of the templates.

Sort list of templates.

Fix cover invocation in tox.ini.

Change-Id: I3edb3d275a078b3be30c9a6f339fab9321601ec8

.zuul.yaml

@@ -1,20 +1,13 @@
 - project:
-    check:
-      jobs:
-        - openstack-tox-lower-constraints
-    gate:
-      jobs:
-        - openstack-tox-lower-constraints
     templates:
-      - openstack-python-jobs
-      - openstack-python35-jobs
-      - publish-openstack-docs-pti
       - check-requirements
       - lib-forward-testing
       - lib-forward-testing-python3
-      - release-notes-jobs-python3
-      - periodic-stable-jobs
+      - openstack-cover-jobs
+      - openstack-lower-constraints-jobs
+      - openstack-python-jobs
+      - openstack-python35-jobs
       - openstack-python36-jobs
-    post:
-      jobs:
-        - openstack-tox-cover
+      - periodic-stable-jobs
+      - publish-openstack-docs-pti
+      - release-notes-jobs-python3

tox.ini

@@ -32,7 +32,14 @@ commands = python setup.py build_sphinx
 
 [testenv:cover]
 basepython = python3
-commands = python setup.py test --coverage --coverage-package-name=oslo_i18n --testr-args='{posargs}'
+setenv =
+    PYTHON=coverage run --source oslo_i18n --parallel-mode
+commands =
+    stestr run '{posargs}'
+    coverage combine
+    coverage html -d cover
+    coverage xml -o cover/coverage.xml
+
 
 [flake8]
 # E123, E125 skipped as they are invalid PEP-8.