[Core] Fix to stay backward compatible after removing SystemId class

Author: alexrobin

sensorhub-datastore-h2/src/main/java/org/sensorhub/impl/datastore/h2/kryo/PersistentClassResolver.java

@@ -113,6 +113,9 @@ protected String mapClassName(String className)
         if (className.startsWith("com.vividsolutions"))
             return className.replace("com.vividsolutions", "org.locationtech");
 
+        else if (className.equals("org.sensorhub.api.system.SystemId"))
+            return "org.sensorhub.api.feature.FeatureId";
+        
         return className;
     }