fix env_vars creating

Change-Id: If6ce954c21fb8dc8d0e5aff584254380647a8b70
diff --git a/cleanup-pipeline.groovy b/cleanup-pipeline.groovy
index a2949eb..948de72 100644
--- a/cleanup-pipeline.groovy
+++ b/cleanup-pipeline.groovy
@@ -45,7 +45,7 @@
 
         } else if (STACK_TYPE == 'aws') {
 
-            env_vars = aws.getEnvVars(AWS_API_CREDENTIALS, AWS_STACK_REGION)
+            env_vars = aws.getEnvVars(AWS_API_CREDENTIALS, AWS_DEFAULT_REGION)
             aws.setupVirtualEnv(venv_path)
 
         } else {