Fix warning by removing unused import

src/test/java/net/floodlightcontroller/core/internal/ControllerTest.java

@@ -38,7 +38,6 @@ import net.floodlightcontroller.core.IHAListener;
 import net.floodlightcontroller.core.IFloodlightProviderService.Role;
 import net.floodlightcontroller.core.IOFMessageFilterManagerService;
 import net.floodlightcontroller.core.IOFMessageListener;
-import net.floodlightcontroller.core.IFloodlightProviderService.Role;
 import net.floodlightcontroller.core.IOFMessageListener.Command;
 import net.floodlightcontroller.core.IOFSwitch;
 import net.floodlightcontroller.core.IOFSwitchListener;