delete reconciliation support on termination points

delete reconciliation support on termination points

Descripion:
There exists chances of stale tunnel-ports left over under following
scenario.

1) DPN connected and Tunnel configuration pushed in by ODL.
2) DPN disconnected and Tunnel Configuation delete by ODL from
network-topology config DS.
3) On DPN connecting back, there exists stale tunnelport port on this
DPN.

Following Changes are done to handle delete reconciliation support.

1) Configure "created_by:odl" on tunnel port in OVS(Port, Interface)
which will be pushed by ovsdb plugin.
2) During reconcilation, compare the termination points available in
config and oper DS and trigger delete of those stale termination points
of Oper DS which are set with "created_by:odl"

JIRA: OVSDB-459

Change-Id: I9356d5ef0af44334c97b6cf3632d4ce9fd2070aa
Signed-off-by: Chetan Arakere Gowdru <chetan.arakere@altencalsoftlabs.com>
Signed-off-by: xcheara <chetan.arakere@altencalsoftlabs.com>