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/opencontrail-upgrade.groovy b/opencontrail-upgrade.groovy
index 7e8412b..311cfef 100644
--- a/opencontrail-upgrade.groovy
+++ b/opencontrail-upgrade.groovy
@@ -54,7 +54,7 @@
 node() {
 
     stage('Setup virtualenv for Pepper') {
-        python.setupPepperVirtualenv(venvPepper, SALT_MASTER_URL, SALT_MASTER_CREDENTIALS)
+        python.setupPepperVirtualenv(pepperEnv, SALT_MASTER_URL, SALT_MASTER_CREDENTIALS)
     }
 
     if (STAGE_CONTROLLERS_UPGRADE.toBoolean() == true && !errorOccured) {