NETVIRT-1293: Stales not getting cleaned up upon neutron v2 driver
Stale flows and interfaces have been observed upon resync of deleted neutron
resources with v2 driver resync after reconnection of ODL.
Failure in reads to deleted neutron resources was leading to returning from
executing deletions. This has been fixed with this patch.
Also, the following has been done:
1. Added debug logs for VPN related operations
2. Prevented a few possible NPEs
3. Minor cleanup
Change-Id: I87fa788b70e28a68fba203e9399364b9b2cb2a04
Signed-off-by: Abhinav Gupta <abhinav.gupta@ericsson.com>