Netconf stack by default locks the data store before issuing edit-config, and then unlocks it.

This poses some scalabilty issues when multiple requests  for the same device arrives. Also some devices automatically queues the requests at the device itself.

This story is about:

1. Providing an option at the device mount time to lock/unlock or not. Default value is true which defaults to today's behavior.
2. If it is set to false then do not issue lock/unlock before edit-config.