[ONOS-5580] Bug fix for JSON encoding of augmented node names

The submission contains:

1. Fix of ONOS-5580
2. Enable RESTCONF server to register and receive notifications from YMS

Change-Id: I8d27a7ee59679de22b7f49b370b35e48909958a4
diff --git a/protocols/restconf/server/rpp/src/main/webapp/WEB-INF/web.xml b/protocols/restconf/server/rpp/src/main/webapp/WEB-INF/web.xml
index c738da9..21cc8a5 100644
--- a/protocols/restconf/server/rpp/src/main/webapp/WEB-INF/web.xml
+++ b/protocols/restconf/server/rpp/src/main/webapp/WEB-INF/web.xml
@@ -28,6 +28,7 @@
             <param-value>org.onosproject.protocol.restconf.server.rpp.RestconfProtocolProxy</param-value>
         </init-param>
         <load-on-startup>1</load-on-startup>
+        <async-supported>true</async-supported>
     </servlet>
 
     <servlet-mapping>