switch to ImmutableList

Change-Id: Ia5f8936d0aaf447253f5dde0db1ee688441d2472
diff --git a/core/store/serializers/src/main/java/org/onlab/onos/store/serializers/KryoNamespaces.java b/core/store/serializers/src/main/java/org/onlab/onos/store/serializers/KryoNamespaces.java
index cbb2bc5..9de6d8c 100644
--- a/core/store/serializers/src/main/java/org/onlab/onos/store/serializers/KryoNamespaces.java
+++ b/core/store/serializers/src/main/java/org/onlab/onos/store/serializers/KryoNamespaces.java
@@ -8,6 +8,7 @@
 import org.onlab.onos.cluster.ControllerNode;
 import org.onlab.onos.cluster.DefaultControllerNode;
 import org.onlab.onos.cluster.NodeId;
+import org.onlab.onos.cluster.RoleInfo;
 import org.onlab.onos.mastership.MastershipTerm;
 import org.onlab.onos.net.ConnectPoint;
 import org.onlab.onos.net.DefaultAnnotations;
@@ -107,7 +108,8 @@
                     Criterion.Type.class,
                     DefaultTrafficTreatment.class,
                     Instructions.DropInstruction.class,
-                    Instructions.OutputInstruction.class
+                    Instructions.OutputInstruction.class,
+                    RoleInfo.class
                     )
             .register(URI.class, new URISerializer())
             .register(NodeId.class, new NodeIdSerializer())