MDEV-21489 : wsrep_cluster_conf_id has wrong value

Do not show exact value as it depends order of test execution.
Instead use # for correct values and ERROR for incorrect.

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

@@ -3,8 +3,8 @@ connection node_1;
 connection node_1;
 show status like 'wsrep_cluster_conf_id';
 Variable_name	Value
-wsrep_cluster_conf_id	2
+wsrep_cluster_conf_id	#
 connection node_2;
 show status like 'wsrep_cluster_conf_id';
 Variable_name	Value
-wsrep_cluster_conf_id	2
+wsrep_cluster_conf_id	#

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

 --source include/galera_cluster.inc
 
 --connection node_1
+--replace_regex /18446744073709551/ERROR/ /[0-9]/#/
 show status like 'wsrep_cluster_conf_id';
 
 --connection node_2
+--replace_regex /18446744073709551/ERROR/ /[0-9]/#/
 show status like 'wsrep_cluster_conf_id';