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/openstack-compute-upgrade.groovy b/openstack-compute-upgrade.groovy
index 3812871..46634bc 100644
--- a/openstack-compute-upgrade.groovy
+++ b/openstack-compute-upgrade.groovy
@@ -29,7 +29,7 @@
     try {
 
         stage('Setup virtualenv for Pepper') {
-            python.setupPepperVirtualenv(venvPepper, SALT_MASTER_URL, SALT_MASTER_CREDENTIALS)
+            python.setupPepperVirtualenv(pepperEnv, SALT_MASTER_URL, SALT_MASTER_CREDENTIALS)
         }
 
         stage('List target servers') {