Infinite loop while vpn instance removal

Sometimes VpnInstanceListener gets into endless loop because not all vpn interfaces removed successfully from VpnToDpnList of the operational/odl-l3vpn:vpn-instance-op-data model.

Analysis:
The current interface counter value inside the function waitForOpRemoval() can be less that original counter, but still not zero, then we are back to beginning of the cycle without any action and sleep again .
The infinite loop doesn’t allow to DataStoreJobCoordinator to run any other job within same key.

Please see an example in the attached log, the vpnname ccc2cbb7-efaa-4243-91fb-bc89f3f549db.