Retire openstack/networking-ovn repository

During Ussuri cycle code from this repository has been
moved to Neutron [1].

All changes to master branch will not be accepted, but we will
keep stable branches and accept bug fixes.

Announcement:
http://lists.openstack.org/pipermail/openstack-discuss/2020-April/014307.html
http://lists.openstack.org/pipermail/openstack-discuss/2020-April/014308.html

[1] https://blueprints.launchpad.net/neutron/+spec/neutron-ovn-merge

Change-Id: Idaa872b6cb226d3b28b8f506544ffcc044528ddd

gerrit/projects.yaml

@@ -3657,8 +3657,6 @@
   description: Neutron drivers for Open Network Operating System.
 - project: openstack/networking-ovn
   description: Neutron integration with OVN
-  options:
-    - translate
 - project: openstack/networking-powervm
   description: Neutron drivers for PowerVM network management.
 - project: openstack/networking-sfc

zuul.d/projects.yaml

@@ -2519,15 +2519,15 @@
 - project:
     name: openstack/networking-ovn
     templates:
-      - translation-jobs-master-stable
-      - periodic-jobs-with-neutron-lib-master
-      - periodic-jobs-with-ovsdbapp-master
       - publish-to-pypi
-    periodic:
+    check:
       jobs:
-        - openstack-tox-py36-with-ovsdbapp-master:
-            required-projects:
-              - openstack/neutron
+        - noop:
+            branches: master
+    gate:
+      jobs:
+        - noop:
+            branches: master
 
 - project:
     name: openstack/networking-powervm