Drop nodesets with ubuntu-xenial

The ubuntu-xenial labels are going to disappear from opendev as that
image is EOL and will we deleted. Clean up our zuul config.

Update some example reference as well.

Change-Id: Id04110f7c871caa1739ff2b62e9796be4fb9aa00
diff --git a/.zuul.yaml b/.zuul.yaml
index 47466cb..13b4633 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -1,14 +1,4 @@
 - nodeset:
-    name: openstack-single-node
-    nodes:
-      - name: controller
-        label: ubuntu-xenial
-    groups:
-      - name: tempest
-        nodes:
-          - controller
-
-- nodeset:
     name: openstack-single-node-jammy
     nodes:
       - name: controller
@@ -39,16 +29,6 @@
           - controller
 
 - nodeset:
-    name: openstack-single-node-xenial
-    nodes:
-      - name: controller
-        label: ubuntu-xenial
-    groups:
-      - name: tempest
-        nodes:
-          - controller
-
-- nodeset:
     name: devstack-single-node-centos-7
     nodes:
       - name: controller
@@ -119,36 +99,6 @@
           - controller
 
 - nodeset:
-    name: openstack-two-node
-    nodes:
-      - name: controller
-        label: ubuntu-xenial
-      - name: compute1
-        label: ubuntu-xenial
-    groups:
-      # Node where tests are executed and test results collected
-      - name: tempest
-        nodes:
-          - controller
-      # Nodes running the compute service
-      - name: compute
-        nodes:
-          - controller
-          - compute1
-      # Nodes that are not the controller
-      - name: subnode
-        nodes:
-          - compute1
-      # Switch node for multinode networking setup
-      - name: switch
-        nodes:
-          - controller
-      # Peer nodes for multinode networking setup
-      - name: peers
-        nodes:
-          - compute1
-
-- nodeset:
     name: openstack-two-node-centos-9-stream
     nodes:
       - name: controller
@@ -269,36 +219,6 @@
           - compute1
 
 - nodeset:
-    name: openstack-two-node-xenial
-    nodes:
-      - name: controller
-        label: ubuntu-xenial
-      - name: compute1
-        label: ubuntu-xenial
-    groups:
-      # Node where tests are executed and test results collected
-      - name: tempest
-        nodes:
-          - controller
-      # Nodes running the compute service
-      - name: compute
-        nodes:
-          - controller
-          - compute1
-      # Nodes that are not the controller
-      - name: subnode
-        nodes:
-          - compute1
-      # Switch node for multinode networking setup
-      - name: switch
-        nodes:
-          - controller
-      # Peer nodes for multinode networking setup
-      - name: peers
-        nodes:
-          - compute1
-
-- nodeset:
     name: openstack-three-node-focal
     nodes:
       - name: controller
diff --git a/functions-common b/functions-common
index 5238dff..8ea6df7 100644
--- a/functions-common
+++ b/functions-common
@@ -401,9 +401,9 @@
 # such as "install_package" further abstract things in better ways.
 #
 # ``os_VENDOR`` - vendor name: ``Ubuntu``, ``Fedora``, etc
-# ``os_RELEASE`` - major release: ``16.04`` (Ubuntu), ``23`` (Fedora)
+# ``os_RELEASE`` - major release: ``22.04`` (Ubuntu), ``23`` (Fedora)
 # ``os_PACKAGE`` - package type: ``deb`` or ``rpm``
-# ``os_CODENAME`` - vendor's codename for release: ``xenial``
+# ``os_CODENAME`` - vendor's codename for release: ``jammy``
 
 declare -g os_VENDOR os_RELEASE os_PACKAGE os_CODENAME