The patch fixes typo

The patch fixes a small typo.

Change-Id: I881131d6b6048b8089e6d643df346889ace5be04
diff --git a/cloud-deploy-pipeline.groovy b/cloud-deploy-pipeline.groovy
index 9c3943b..5ae3d28 100644
--- a/cloud-deploy-pipeline.groovy
+++ b/cloud-deploy-pipeline.groovy
@@ -79,7 +79,7 @@
 
 def slave_node = 'python'
 
-if (common.validInputParam(SLAVE_NODE)) {
+if (common.validInputParam('SLAVE_NODE')) {
     slave_node = SLAVE_NODE
 }