General link discovery module cleanup.

* Removed all events we don't use from the event system (switch and port
  events, link updates)
* Refactored event interface to two separate methods to match the other event
  interfaces
* Removed the LDUpdate class and moved all the event enums and classes to be
  internal to the LinkDiscoveryManager
* Removed all LinkTypes we no longer used and moved the one remaining type
  to the ILinkDiscoveryService. After this the ILinkDiscovery interface is
  no longer needed.
* Made Link immutable
* Removed the linkdiscovery.internal package as it only contained one class
* Readability improvements to LinkDiscoveryManager

Change-Id: Ifae97879aadc49b70a7b3d2294dcc540538c2cfc
diff --git a/src/test/java/net/floodlightcontroller/core/internal/ControllerTest.java b/src/test/java/net/floodlightcontroller/core/internal/ControllerTest.java
index 8f69e64..eb63904 100644
--- a/src/test/java/net/floodlightcontroller/core/internal/ControllerTest.java
+++ b/src/test/java/net/floodlightcontroller/core/internal/ControllerTest.java
@@ -56,7 +56,7 @@
 import net.floodlightcontroller.test.FloodlightTestCase;
 import net.floodlightcontroller.threadpool.IThreadPoolService;
 import net.onrc.onos.core.linkdiscovery.ILinkDiscoveryService;
-import net.onrc.onos.core.linkdiscovery.internal.LinkDiscoveryManager;
+import net.onrc.onos.core.linkdiscovery.LinkDiscoveryManager;
 import net.onrc.onos.core.main.IOFSwitchPortListener;
 import net.onrc.onos.core.packet.ARP;
 import net.onrc.onos.core.packet.Ethernet;