[ovn] Use ubuntu minimal as advanced image

Current kernel in Ubuntu focal minimal image
is 5.4.0-1082-kvm and that includes the fix for
missing multicast feature[1], let's use the
minimal image in ovn jobs too like other scenario
jobs[2].

Cannot use minimal image in releases before victoria
as those are pinned to neutron-tempest-plugin-1.6.0
and the required patch [3] is only available since
1.8.0. victoria jobs already have advanced image
specific overrides, added overrides in ussuri ovn job.

[1] https://bugs.launchpad.net/cloud-images/+bug/1946672
[2] https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/813195
[3] https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/813195

Related-Bug: #1948804
Change-Id: Ibe180fc6d1785682033886faf8ba03323bb1a3e8
diff --git a/zuul.d/ussuri_jobs.yaml b/zuul.d/ussuri_jobs.yaml
index 8614fa9..77e2530 100644
--- a/zuul.d/ussuri_jobs.yaml
+++ b/zuul.d/ussuri_jobs.yaml
@@ -254,6 +254,12 @@
         OVN_BRANCH: "v20.03.0"
         # NOTE(slaweq): IGMP Snooping requires OVN 20.12
         OVN_IGMP_SNOOPING_ENABLE: False
+        # NOTE(bcafarel) guestmount binary not available on host OS
+        IMAGE_URLS: https://cloud-images.ubuntu.com/releases/bionic/release/ubuntu-18.04-server-cloudimg-amd64.img
+        ADVANCED_IMAGE_NAME: ubuntu-18.04-server-cloudimg-amd64
+        ADVANCED_INSTANCE_TYPE: ds512M
+        ADVANCED_INSTANCE_USER: ubuntu
+        CUSTOMIZE_IMAGE: false
       devstack_local_conf:
         test-config:
           $TEMPEST_CONFIG: