[OVN] Set OVN bridge in Chassis_Private in OVN agent

The method ``MetadataAgent._update_chassis_private_config`` is called in
the OVN metadata agent to update the corresponding Chassis_Private
register; in this case, with the OVN bridge used (that by default is
usually "br-int").

This call was missing from the OVN agent "metadata" extension, both
in the initialization method and in the resync.

Closes-Bug: #2112314
Change-Id: Ia22572d8953c3bade5bfd9950a2d83e050847d65
(cherry picked from commit 5cfc1d5)

Author: ralonsoh

neutron/agent/ovn/extensions/metadata.py

@@ -161,6 +161,7 @@ def resync(self):
         Reload the configuration and sync the agent again.
         """
         self.agent_api.load_config()
+        self._update_chassis_private_config()
         self.agent_api.update_neutron_sb_cfg_key()
         self.sync()
 
@@ -178,6 +179,7 @@ def start(self):
 
         # Register the agent with its corresponding Chassis
         self.register_metadata_agent()
+        self._update_chassis_private_config()
         self.agent_api.update_neutron_sb_cfg_key()
 
         # Start the metadata server.

neutron/tests/functional/agent/ovn/agent/test_ovn_neutron_agent.py

@@ -135,10 +135,12 @@ def test_check_metadata_started(self):
         # Check the metadata extension is registered.
         chassis_id = uuid.UUID(self.chassis_name)
         agent_id = uuid.uuid5(chassis_id, 'metadata_agent')
+        ext_ids = {ovn_const.OVN_AGENT_METADATA_ID_KEY: str(agent_id),
+                   ovn_const.OVN_AGENT_OVN_BRIDGE: 'br-int',
+                   ovn_const.OVN_AGENT_NEUTRON_SB_CFG_KEY: '0',
+                   }
         ch_private = self.sb_api.lookup('Chassis_Private', self.chassis_name)
-        self.assertEqual(
-            ch_private.external_ids[ovn_const.OVN_AGENT_METADATA_ID_KEY],
-            str(agent_id))
+        self.assertEqual(ext_ids, ch_private.external_ids)
 
         # Check Unix proxy is running.
         metadata_extension = self.ovn_agent[METADATA_EXTENSION]