Fix default vm images

Change-Id: I34bc0fb1278f9e33209c90789b62f0e23b9a322e
Prod-related: PROD-30962 (PROD:30962)
diff --git a/salt/control/cluster/openstack_benchmark_single.yml b/salt/control/cluster/openstack_benchmark_single.yml
index 814f65a..3d2bacd 100644
--- a/salt/control/cluster/openstack_benchmark_single.yml
+++ b/salt/control/cluster/openstack_benchmark_single.yml
@@ -1,6 +1,6 @@
 parameters:
   _param:
-    openstack_benchmark_backend_image: ${_param:salt_control_trusty_image_backend}
+    openstack_benchmark_backend_image: ${_param:salt_control_xenial_image_backend}
     salt_control_cluster_node_cloud_init_openstack_benchmark:
       user_data:
         write_files:
@@ -25,7 +25,7 @@
             bmk01:
               name: ${_param:openstack_benchmark_node01_hostname}
               provider: ${_param:infra_kvm_node03_hostname}.${_param:cluster_domain}
-              image: ${_param:salt_control_trusty_image}
+              image: ${_param:salt_control_xenial_image}
               backend: ${_param:openstack_benchmark_backend_image}
               size: openstack.benchmark
               cloud_init: ${_param:salt_control_cluster_node_cloud_init_openstack_benchmark}