bug 8674 fix port vlan bindings reconciliation

bug 8674 fix port vlan bindings reconciliation

1. When controller is restarted after clearing the config by
removing journals and snapshots, it does not have any config data
for ports.

Do not fire delete of port during reconciliation.
Fire port update to clear the vlan bindings.
Port addition/deletion is always managed by southbound not by controller.
Only port update is managed by controller.

2. Sometimes logical switch does not get deleted from device due to some
local ucast/mcast references to it. Cleanup the references also while
deleting the logical switch. It can still fail if vlan binding reference
is not removed.

3. Make sure that mcast and ucast programming during reconciliation
uses proper physical locators.

Change-Id: I81f095a6e030e05d6702997600ced012d4666c36
Signed-off-by: K.V Suneelu Verma <k.v.suneelu.verma@ericsson.com>