Fix setting random username for Ironic

Change-Id: I72f8045ded17eb8617b58cc7bed907285cc649ae
Related-Prod: PROD-32745
diff --git a/ironic/api/single.yml b/ironic/api/single.yml
index 0e5d61e..fdc4ac7 100644
--- a/ironic/api/single.yml
+++ b/ironic/api/single.yml
@@ -16,6 +16,7 @@
       bind:
         address: ${_param:single_address}
       database:
+        user: ${_param:mysql_ironic_username}
         x509:
           enabled: ${_param:openstack_mysql_x509_enabled}
           ca_file: ${_param:mysql_ironic_ssl_ca_file}