Fix test case wsrep.mdev_6832 we need to wait until wsrep_ready

is ON before test can end.

mysql-test/suite/wsrep/t/mdev_6832.test

@@ -12,5 +12,6 @@ eval SET @@global.wsrep_provider='$WSREP_PROVIDER';
 --enable_query_log
 SHOW STATUS LIKE 'wsrep_ready';
 SET @@global.wsrep_cluster_address='gcomm://';
-
+--let $wait_condition = SELECT VARIABLE_VALUE = 'ON' FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_ready';
+--source include/wait_condition.inc
 --echo # End of test.