Issue in flow programming:

Issue in flow programming:
	Add a flow, uninstall it, try to remove it. Remove seems to fail from gui behavior.
	Try to install the flow. It will fail and uncaught exception in forwardingrulesmanager is printed.
Fix:
	Handle invalid flow status toggle request in forwardingrulesmanager.
	IForwardingrulesmanager to exposed a per node and per flow name api for toggling the flow status.
	Flow.web to evaluate api return status by status code and not by status description,
	because a Status with StatusCode.SUCCESS does not imply the description is "Success".

Change-Id: I33567b473828721bd6548ea222f4b7bcf83c0306
Signed-off-by: aboch <aboch@cisco.com>