BUG 956 - thread problem
thread problem fixed
added unit tests
OFRpcTaskFactory.createUpdateFlowTask changed - result from flow removing used in further processing
port stats repaired

Change-Id: Idef68139ced6eb5db7a29fb1eb302a105b7a1a4c
Signed-off-by: Timotej Kubas <tkubas@cisco.com>
Signed-off-by: Michal Rehak <mirehak@cisco.com>