modules/cdp: set CDP session to 0 after free-ing

modules/cdp/authstatemachine.c

@@ -248,6 +248,7 @@ inline int auth_client_statefull_sm_process(cdp_session_t* s, int event, AAAMess
                 case AUTH_EV_SERVICE_TERMINATED:
                 case AUTH_EV_SESSION_GRACE_TIMEOUT:
                     cdp_session_cleanup(s, NULL);
+		    s==0;
                     break;
 
                 default: