[WIP] Upgrade ONOS to karaf version 4.2.1

Change-Id: I7cd40c995bdf1c80f94b1895fb3344e32404c7fa
diff --git a/cli/src/main/java/org/onosproject/cli/net/LeaderCommand.java b/cli/src/main/java/org/onosproject/cli/net/LeaderCommand.java
index 51601d2..7139b86 100644
--- a/cli/src/main/java/org/onosproject/cli/net/LeaderCommand.java
+++ b/cli/src/main/java/org/onosproject/cli/net/LeaderCommand.java
@@ -18,9 +18,10 @@
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ArrayNode;
-import org.apache.karaf.shell.commands.Argument;
-import org.apache.karaf.shell.commands.Command;
-import org.apache.karaf.shell.commands.Option;
+import org.apache.karaf.shell.api.action.Argument;
+import org.apache.karaf.shell.api.action.Command;
+import org.apache.karaf.shell.api.action.lifecycle.Service;
+import org.apache.karaf.shell.api.action.Option;
 import org.onlab.util.Tools;
 import org.onosproject.cli.AbstractShellCommand;
 import org.onosproject.cluster.Leadership;
@@ -35,6 +36,7 @@
 /**
  * Prints the leader for every topic.
  */
+@Service
 @Command(scope = "onos", name = "leaders",
         description = "Finds the leader for particular topic.")
 public class LeaderCommand extends AbstractShellCommand {
@@ -134,7 +136,7 @@
     }
 
     @Override
-    protected void execute() {
+    protected void doExecute() {
         LeadershipAdminService leaderService = get(LeadershipAdminService.class);
         Map<String, Leadership> leaderBoard = leaderService.getLeaderBoard();
         if (topicPattern == null) {