Bug 1181 : of-flow: Flow match criteria (ipv6-source,ipv6-destination) is different in config and operational database

- added unit test

Change-Id: I186d9bdd67a62fa8f98606a8f3ad76d99ef56fec
Signed-off-by: Anilkumar Vishnoi <avishnoi@in.ibm.com>
Signed-off-by: Michal Rehak <mirehak@cisco.com>