MDEV-21489 : wsrep_cluster_conf_id has wrong value

Variable was not updated after initialization.

mysql-test/suite/galera/r/galera_var_cluster_conf_id.result

+connection node_2;
+connection node_1;
+connection node_1;
+show status like 'wsrep_cluster_conf_id';
+Variable_name	Value
+wsrep_cluster_conf_id	2
+connection node_2;
+show status like 'wsrep_cluster_conf_id';
+Variable_name	Value
+wsrep_cluster_conf_id	2

mysql-test/suite/galera/t/galera_var_cluster_conf_id.test

+--source include/galera_cluster.inc
+
+--connection node_1
+show status like 'wsrep_cluster_conf_id';
+
+--connection node_2
+show status like 'wsrep_cluster_conf_id';

sql/wsrep_server_service.cc

@@ -201,6 +201,7 @@ void Wsrep_server_service::log_view(
   wsrep_update_cluster_state_uuid(os.str().c_str());
   mysql_mutex_unlock(&LOCK_status);
   wsrep_config_state->set(view);
+  wsrep_cluster_conf_id= view.view_seqno().get();
 
   if (view.status() == wsrep::view::primary)
   {