Merge remote-tracking branch 'upstream/master'

...t/floodlightcontroller/devicemanager/internal/Device.java

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

...et/floodlightcontroller/linkdiscovery/ILinkDiscovery.java

...ntroller/linkdiscovery/internal/LinkDiscoveryManager.java

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

...va/net/floodlightcontroller/topology/TopologyManager.java

...troller/devicemanager/internal/DeviceManagerImplTest.java

...htcontroller/virtualnetwork/VirtualNetworkFilterTest.java