Eliminating SwitchClusterId in IOFSwitch interface.

src/main/java/net/floodlightcontroller/core/IOFSwitch.java

...floodlightcontroller/core/web/SwitchClustersResource.java

...dlightcontroller/devicemanager/DeviceAttachmentPoint.java

...tcontroller/devicemanager/internal/DeviceManagerImpl.java

.../java/net/floodlightcontroller/forwarding/Forwarding.java

...java/net/floodlightcontroller/routing/ForwardingBase.java

...va/net/floodlightcontroller/topology/BroadcastDomain.java

...a/net/floodlightcontroller/topology/ITopologyService.java

...java/net/floodlightcontroller/topology/SwitchCluster.java

.../floodlightcontroller/topology/internal/TopologyImpl.java

...a/net/floodlightcontroller/forwarding/ForwardingTest.java

...odlightcontroller/topology/internal/TopologyImplTest.java