Support JSON output in external router CLI, make router obj immutable

Change-Id: I6c76d9aafd64c1af7c3e28b42beabc268f824b88
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/MacAddressCompleter.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/MacAddressCompleter.java
index 6e21de6..3b6e475 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/MacAddressCompleter.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/MacAddressCompleter.java
@@ -38,7 +38,7 @@
         StringsCompleter delegate = new StringsCompleter();
         OpenstackNetworkService osNetService = AbstractShellCommand.get(OpenstackNetworkService.class);
         Set<MacAddress> set = osNetService.externalPeerRouters().stream()
-                .map(ExternalPeerRouter::externalPeerRouterMac)
+                .map(ExternalPeerRouter::macAddress)
                 .collect(Collectors.toSet());
         SortedSet<String> strings = delegate.getStrings();