[Train Only] Drop networking-ovn jobs

networking-ovn is marked eol with [1], this patch
drops the job too.

[1] https://review.opendev.org/c/openstack/releases/+/865967

Depends-On: https://review.opendev.org/c/openstack/devstack/+/872902
Depends-On: https://review.opendev.org/c/openstack/grenade/+/872999
Depends-On: https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/873060
Depends-On: https://review.opendev.org/c/openstack/openstack-zuul-jobs/+/873056
Change-Id: Ie22f00bc82cbd754ca4d3514d6935cb51898c27c

.zuul.yaml

@@ -35,8 +35,6 @@
               - ^setup.cfg$
               - ^tools/.*$
               - ^tox.ini$
-        - networking-ovn-tempest-dsvm-ovs-release:
-            irrelevant-files: *tempest-irrelevant-files
         - tempest-integrated-networking
         - openstacksdk-functional-devstack
         - grenade: