Add victoria/wallaby stable branch jobs on master gate

We have stable/victoria and stable/wallaby released so we
should add their job on master gate to keep branchless
tempest plugins compatible to those branch.

This also removes the stable/stein job as that is in EM
state now.

Ref: Tempest plugins guide for stable branch testing:
- https://docs.openstack.org/tempest/latest/stable_branch_testing_policy.html

Change-Id: Ic60d898969e730fcf1aebc4d103f06ec0baf24ed

.zuul.yaml

@@ -44,9 +44,10 @@
         - keystone-dsvm-py3-functional-federation-ubuntu-focal:
             voting: false
         - keystone-dsvm-py3-functional-federation-ubuntu-focal-k2k
+        - keystone-dsvm-py3-functional-wallaby
+        - keystone-dsvm-py3-functional-victoria
         - keystone-dsvm-py3-functional-ussuri
         - keystone-dsvm-py3-functional-train
-        - keystone-dsvm-py3-functional-stein
         - keystone-protection-functional
     gate:
       jobs:
@@ -54,6 +55,16 @@
         - keystone-dsvm-py3-functional-federation-ubuntu-focal-k2k
         - keystone-protection-functional
 
+- job:
+    name: keystone-dsvm-py3-functional-wallaby
+    parent: keystone-dsvm-py3-functional
+    override-checkout: stable/wallaby
+
+- job:
+    name: keystone-dsvm-py3-functional-victoria
+    parent: keystone-dsvm-py3-functional
+    override-checkout: stable/victoria
+
 - job:
     name: keystone-dsvm-py3-functional-ussuri
     parent: keystone-dsvm-py3-functional
@@ -65,9 +76,3 @@
     parent: keystone-dsvm-py3-functional
     nodeset: openstack-single-node-bionic
     override-checkout: stable/train
-
-- job:
-    name: keystone-dsvm-py3-functional-stein
-    parent: keystone-dsvm-py3-functional
-    nodeset: openstack-single-node-bionic
-    override-checkout: stable/stein