Trivial fix to run k8s conformance tests

The fix resolves 'No such property: K8S_CONFORMANCE_IMAGE
for class: WorkflowScript' error

Change-Id: I36c9649a732a7e26e7034b701d3ff34d7316d9be
diff --git a/cloud-deploy-pipeline.groovy b/cloud-deploy-pipeline.groovy
index fc0a290..38172c9 100644
--- a/cloud-deploy-pipeline.groovy
+++ b/cloud-deploy-pipeline.groovy
@@ -381,7 +381,7 @@
             }
 
             stage('Run k8s conformance e2e tests') {
-                def image = K8S_CONFORMANCE_IMAGE
+                def image = TEST_K8S_CONFORMANCE_IMAGE
                 def output_file = image.replaceAll('/', '-') + '.output'
 
                 // run image