Add Patrole gate job for stable/train

Now we have stable/train branch ready for devstack
and so does for all service projects.

This commit adds the Patrole testing for stable/train
by adding new jobs running on stable/train version of
openstack.

Depends-On: https://review.opendev.org/#/c/701404/

Change-Id: I3655cf176f12685dd87c52d8e4979d8f8e000a38

.zuul.yaml

@@ -93,6 +93,14 @@
       devstack_localrc:
         RBAC_TEST_ROLES: reader
 
+- job:
+    name: patrole-member-train
+    parent: patrole-member
+    override-checkout: stable/train
+    vars:
+      devstack_localrc:
+        USE_PYTHON3: True
+
 - job:
     name: patrole-member-stein
     parent: patrole-member
@@ -192,6 +200,7 @@
         - patrole-admin
         - patrole-member
         - patrole-reader
+        - patrole-member-train
         - patrole-member-stein
         - patrole-multinode-admin
         - patrole-multinode-member
@@ -203,4 +212,5 @@
         - patrole-member
     periodic-stable:
       jobs:
+        - patrole-member-train
         - patrole-member-stein

devstack/plugin.sh

@@ -105,6 +105,11 @@ function install_patrole_tempest_plugin {
        iniset $TEMPEST_CONFIG policy-feature-enabled changed_nova_policies_ussuri False
     fi
 
+    if [[ ${DEVSTACK_SERIES} == 'train' ]]; then
+       # Remove this once stable/train becomes EOL.
+       iniset $TEMPEST_CONFIG policy-feature-enabled changed_nova_policies_ussuri False
+    fi
+
     iniset $TEMPEST_CONFIG patrole rbac_test_roles $RBAC_TEST_ROLES
 }