Refactor Comparator class to break dependency of core/net on the CLI

Change-Id: I6f3165f399ab448eff5c5d2232f4b96f10ebf57e
diff --git a/cli/src/main/java/org/onosproject/cli/NodesListCommand.java b/cli/src/main/java/org/onosproject/cli/NodesListCommand.java
index 50e8d53..6e91738 100644
--- a/cli/src/main/java/org/onosproject/cli/NodesListCommand.java
+++ b/cli/src/main/java/org/onosproject/cli/NodesListCommand.java
@@ -24,6 +24,7 @@
 import org.onlab.util.Tools;
 import org.onosproject.cluster.ClusterService;
 import org.onosproject.cluster.ControllerNode;
+import org.onosproject.utils.Comparators;
 
 import java.util.Collections;
 import java.util.List;