[neutron-api] remove leader_only for sb connection

The maintenance worker from the neutron-api uses a southbound
connection. Since the southbound does not use any locking and all the
ovsdb locking is used for the northbound this changes should not have a
big impact.

This commit removes the leader_only flag for the maintenance worker.
This should also enable the neutron api to connect to relays instead of only
the sb directly.

Closes-Bug: #2022914
Change-Id: Ia7937390867e45af34ebcd65bd76fc89b6adafe9
Signed-off-by: maximkorezkij <[email protected]>
(cherry picked from commit a9c8bf5)

Author: maximkorezkij

neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovsdb_monitor.py

@@ -661,9 +661,8 @@ def from_server(cls, connection_string, helper):
         helper.register_table('Encap')
         helper.register_table('Port_Binding')
         helper.register_table('Datapath_Binding')
-        # Used by MaintenanceWorker which can use ovsdb locking
         try:
-            return cls(connection_string, helper, leader_only=True)
+            return cls(connection_string, helper, leader_only=False)
         except TypeError:
             # TODO(twilson) We can remove this when we require ovs>=2.12.0
             return cls(connection_string, helper)

releasenotes/notes/bug-2022914-edbf1ea3514596b8.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    [`bug 2022914 <https://bugs.launchpad.net/neutron/+bug/2022914>`_]
+    Neutron-API supports using relays as the southbound connection in a
+    ML2/OVN setup. Before the maintenance worker of the API required a
+    leader_only connection, which was removed.