Controller does not delete existing flows from the network at startup (karaf edition)

The controller does not delete existing flows from the network when it starts up empty (i.e. with no existing flows in the config data store) and switches contain some flows.

To reproduce:

1. Start mininet (number of nodes is irrelevant)
2. Start the controller
3. Insert a few flows into the network
4. Restart the controller
5. Validate that inserted flows are still in the network
6. Use the RestAPI to get operational inventory data and validate that
previously inserted flows are still in the network

Only OpenFlow related features and restconf were present for this test.