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-control-upgrade.groovy b/openstack-control-upgrade.groovy
index b2bd621..76960e9 100644
--- a/openstack-control-upgrade.groovy
+++ b/openstack-control-upgrade.groovy
@@ -19,7 +19,7 @@
 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_TEST_UPGRADE.toBoolean() == true) {