Fix container flow logic in forwarding rules manager

Fix container flow logic in forwarding rules manager

- In Activator.java:
   + All instances of FRM must be IContainerListener
   + Pass the right cache name in order to have the save config event working in the cluster
- In ForwardingRulesManaerImpl.java:
   + Add container check filtering in the IContainerListener methods
   + In updateFlowsContainerFlow() first uninstall all current flows, then reinstall instead
     of interleave remove/add which could cause conflict failures during installation phase
     as the new entries could conflict with existing old container flow merged flows present
     on the netwrok node
   + minor logs and style changes
- In FlowEntryInstall.java:
   + Fixed a bug where container flow merging was altering the original flow entry

Signed-off-by: Alessandro Boch <aboch@cisco.com>