Updating iperf public servers list

- setting single image for both AZs

Change-Id: I3406a43b8c3944f1c2d3cc42144cd611a49ccc00
Related-bug: https://mirantis.jira.com/browse/PROD-27569
diff --git a/scenarios/additional/cross_az/l2.hot b/scenarios/additional/cross_az/l2.hot
index 349f68a..3636a49 100644
--- a/scenarios/additional/cross_az/l2.hot
+++ b/scenarios/additional/cross_az/l2.hot
@@ -68,7 +68,7 @@
     type: OS::Nova::Server
     properties:
       name: {{ agent.id }}
-      image: {% if agent.zone == 'vcenter' %} shaker-image-vcenter {% else %} shaker-image-nova {% endif %}
+      image: { get_param: image }
       flavor: { get_param: flavor }
       availability_zone: "{{ agent.availability_zone }}"
       networks: