Clean/Update some comments

Part of ONOS-1925

Change-Id: If507b7728a1f7e91c7697d9082cdc84b6c1fb8ee
diff --git a/src/main/java/net/onrc/onos/core/topology/ImmutableTopologySnapshot.java b/src/main/java/net/onrc/onos/core/topology/ImmutableTopologySnapshot.java
index 3166a6a..0539e18 100644
--- a/src/main/java/net/onrc/onos/core/topology/ImmutableTopologySnapshot.java
+++ b/src/main/java/net/onrc/onos/core/topology/ImmutableTopologySnapshot.java
@@ -578,7 +578,7 @@
             return null;
         }
 
-        // TODO Should we look for Packet link first?
+        // Should we look for Packet link first?
         //  => Not needed unless invariant is broken.
 
         for (LinkEvent link : links.values()) {