Make pepper usage configurable in tempest pipeline

Pepper usage is not required in cases of heat stack
deployments.

Change-Id: I064d8b2c25792e28d95f43eaa41d2ab17ba5d680
Related-Prod: https://mirantis.jira.com/browse/PROD-16009
diff --git a/jenkins/client/job/oscore/tests.yml b/jenkins/client/job/oscore/tests.yml
index 4844708..85346e1 100644
--- a/jenkins/client/job/oscore/tests.yml
+++ b/jenkins/client/job/oscore/tests.yml
@@ -207,6 +207,10 @@
                 type: string
                 description: Tests pass rate to consider build successful
                 default: "90"
+              USE_PEPPER:
+                type: boolean
+                description: Whether to use pepper to connect to salt master
+                default: 'false'
         results-checker-template:
           name: "{{job_prefix}}-{{test_type}}-results-checker"
           template: