Fix typos in reclass for image_layout backends

Change-Id: I259c2265b6b2fac638aa896c1ddec11814740f69
(cherry picked from commit c1d38f91c20c703e543ca5c83d11f63ba789f8aa)
diff --git a/salt/control/cluster/openstack_benchmark_single.yml b/salt/control/cluster/openstack_benchmark_single.yml
index c8223cc..814f65a 100644
--- a/salt/control/cluster/openstack_benchmark_single.yml
+++ b/salt/control/cluster/openstack_benchmark_single.yml
@@ -16,7 +16,7 @@
           ram: 4096
           disk_profile: small
           net_profile: default
-          image_layout: ${_param:salt_control_cluster_node_image_layout_openstack_benchmark}
+          image_layout: ${_param:salt_control_size_image_layout_openstack_benchmark}
       cluster:
         internal:
           domain: ${_param:cluster_domain}