Fix typo in Pepper related changes

- Fix typo in changes which inforcing to use Pepper
  instead of direct http requests.

Change-Id: I34a689d8c89b68b8a5cfa77a96bdfb2a1132d7f6
Closes-Bug: PROD-15207
diff --git a/docker-cleanup-pipeline.groovy b/docker-cleanup-pipeline.groovy
index abc21d1..677efdf 100644
--- a/docker-cleanup-pipeline.groovy
+++ b/docker-cleanup-pipeline.groovy
@@ -16,7 +16,7 @@
 node{
   def saltMaster;
   stage('Setup virtualenv for Pepper') {
-    python.setupPepperVirtualenv(venvPepper, SALT_MASTER_URL, SALT_MASTER_CREDENTIALS)
+    python.setupPepperVirtualenv(pepperEnv, SALT_MASTER_URL, SALT_MASTER_CREDENTIALS)
   }
   stage("Clean old containers"){
     salt.cmdRun(pepperEnv, 'I@jenkins:slave', """