Add job builds discarder

Change-Id: I7a4a46826b547731b91f2ed1f58927ba4ddd4455
diff --git a/jenkins/client/job/deploy/update/upgrade_opencontrail.yml b/jenkins/client/job/deploy/update/upgrade_opencontrail.yml
index de7e46f..0b0d945 100644
--- a/jenkins/client/job/deploy/update/upgrade_opencontrail.yml
+++ b/jenkins/client/job/deploy/update/upgrade_opencontrail.yml
@@ -10,6 +10,11 @@
         deploy-upgrade-opencontrail:
           type: workflow-scm
           concurrent: true
+          discard:
+            build:
+              keep_num: 10
+            artifact:
+              keep_num: 10
           display_name: "Deploy - upgrade Opencontrail"
           scm:
             type: git