Added missing call for WorldUnload event.

src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -588,6 +588,7 @@ public final class CraftServer implements Server {
         }
 
         WorldUnloadEvent e = new WorldUnloadEvent(handle.getWorld());
+        pluginManager.callEvent(new WorldUnloadEvent(handle.getWorld()));
 
         if (e.isCancelled()) {
             return false;