Don't use Ref in hot template (functional test)

This is a template that should fail (for another reason)
but it is causing the nested stack to not get cleaned up.

Change-Id: I501bc279a9f11cc47a89d397055d0aefe0c4bd6e
diff --git a/functional/test_autoscaling.py b/functional/test_autoscaling.py
index 87c4c32..0beefcb 100644
--- a/functional/test_autoscaling.py
+++ b/functional/test_autoscaling.py
@@ -105,7 +105,7 @@
   waiter:
     type: AWS::CloudFormation::WaitCondition
     properties:
-      Handle: {Ref: ready_poster}
+      Handle: {get_resource: ready_poster}
       Timeout: 1
 outputs:
   PublicIp: