[OVN] Add segments to ML2_SUPPORTED_API_EXTENSIONS

We recently added segmented network features to OVN,
that means we could add this extension here to the list.

Change-Id: Iab1fa9d810b3cc2e0384144cf33fc6732d55bec1

neutron/common/ovn/extensions.py

@@ -15,6 +15,7 @@
 from neutron_lib.api.definitions import agent as agent_def
 from neutron_lib.api.definitions import availability_zone as az_def
 from neutron_lib.api.definitions import router_availability_zone as raz_def
+from neutron_lib.api.definitions import segment as seg_def
 
 # NOTE(russellb) This remains in its own file (vs constants.py) because we want
 # to be able to easily import it and export the info without any dependencies
@@ -61,4 +62,5 @@ ML2_SUPPORTED_API_EXTENSIONS = [
     'standard-attr-timestamp',
     'trunk',
     'quota_details',
+    seg_def.ALIAS,
 ]

zuul.d/tempest-multinode.yaml

@@ -165,6 +165,7 @@
         s-proxy: false
         tls-proxy: true
         q-qos: true
+        neutron-segments: True
     group-vars:
       subnode:
         devstack_services: