Fix typo in getHeatStackResourceInfo method call

Change-Id: Ia455148a55de9f29fecd937dd3cde3ea15ce6f6e
diff --git a/src/com/mirantis/mk/Openstack.groovy b/src/com/mirantis/mk/Openstack.groovy
index 879ebd5..91dfbfe 100644
--- a/src/com/mirantis/mk/Openstack.groovy
+++ b/src/com/mirantis/mk/Openstack.groovy
@@ -364,7 +364,7 @@
     servers = [:]
     for (resource in resources) {
         if (resource.resource_type == 'OS::Nova::Server') {
-            server = openstack.getHeatStackResourceInfo(env, resource.stack_name, resource.resource_name, path)
+            server = getHeatStackResourceInfo(env, resource.stack_name, resource.resource_name, path)
             servers[server.attributes.id] = server.attributes.name
         }
     }