Disable voting on openstack-tox-py27

We believe there is a recent change in stestr that might break python27:
af0fdae10d

Until we figure it out, let's disable py27 testing which anyway will be
removed soon once we roll out centos8 testing.

- Disabling voting on openstack-tox-py27
- Remove it from the gate queue
- Stop using the openstack-python-jobs template

Change-Id: I2973ab7c6385f56ccb46f0f0cc82f32cfc56c87c

zuul.d/layout.yaml

@@ -3,7 +3,6 @@
       - check-requirements
       - openstack-lower-constraints-jobs
       - openstackclient-plugin-jobs
-      - openstack-python-jobs
       - openstack-python36-jobs
       - openstack-python37-jobs
       - openstack-python3-train-jobs
@@ -17,13 +16,13 @@
     check:
       jobs:
         - openstack-tox-pep8
-        - openstack-tox-py27
+        - openstack-tox-py27:
+            voting: false
         - openstack-tox-py36
         - openstack-tox-py37
         - tripleo-ci-centos-7-containers-multinode:
             dependencies: &deps_unit_lint
               - openstack-tox-pep8
-              - openstack-tox-py27
               - openstack-tox-py36
               - openstack-tox-py37
         - tripleo-ci-centos-7-scenario000-multinode-oooq-container-upgrades:
@@ -57,3 +56,5 @@
               - ^tripleoclient/v1/tripleo_deploy.py$
     gate:
       queue: tripleo
+      jobs:
+        - openstack-tox-pep8