[OVN] Fix deadlock in neutron_ovn_db_sync_util.py
[OVN] Fix deadlock in neutron_ovn_db_sync_util.py

A feature to synchronize OVN DB connections when handling events
introduced in 90980f496cfa3cc5df1c93cf834a44f33d3f1f6f is not applicable
to the offline sync process executed by this utility.

Closes-bug: #1950679
Change-Id: Iac4eb364bfc1c44f5d4526bae71967bede29cc36

mahak/neutron,mahak/neutron,openstack/neutron,mahak/neutron,openstack/neutron,openstack/neutron