fix STACK_TYPE parameter verification

Change-Id: I77f8d00bc574a17f431c4d5e0d9f652392077fc4
diff --git a/cleanup-pipeline.groovy b/cleanup-pipeline.groovy
index f2c9da0..cd0a463 100644
--- a/cleanup-pipeline.groovy
+++ b/cleanup-pipeline.groovy
@@ -33,12 +33,10 @@
     def env_vars
 
     // default STACK_TYPE is heat
-    if (!common.validInputParam(STACK_TYPE)) {
+    if (!common.validInputParam('STACK_TYPE')) {
         STACK_TYPE = 'heat'
     }
 
-    common.infoMsg("Going to delelete stack type: " + STACK_TYPE)
-
     stage('Install environment') {
         if (STACK_TYPE == 'heat') {