Kryo: set next registration id for local types registered in ECMapImpl

Change-Id: I9483f3b302224f3eb9dbd4e6dfb98a54143e3243
diff --git a/core/store/dist/src/main/java/org/onosproject/store/ecmap/EventuallyConsistentMapImpl.java b/core/store/dist/src/main/java/org/onosproject/store/ecmap/EventuallyConsistentMapImpl.java
index 1fd27d3..6d8daaa 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/ecmap/EventuallyConsistentMapImpl.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/ecmap/EventuallyConsistentMapImpl.java
@@ -244,6 +244,7 @@
                 // Add the map's internal helper classes to the user-supplied serializer
                 serializerPool = builder
                         .register(KryoNamespaces.BASIC)
+                        .nextId(KryoNamespaces.BEGIN_USER_CUSTOM_ID)
                         .register(LogicalTimestamp.class)
                         .register(WallClockTimestamp.class)
                         .register(AntiEntropyAdvertisement.class)