Update gerrit credentials value in vnf jobs

PROD-31174

Change-Id: I0836fe9896f0f9189fd83221233cd827ee94a0fe
diff --git a/jenkins/client/job/deploy/backupninja_backup.yml b/jenkins/client/job/deploy/backupninja_backup.yml
index e798e64..ab5caf0 100644
--- a/jenkins/client/job/deploy/backupninja_backup.yml
+++ b/jenkins/client/job/deploy/backupninja_backup.yml
@@ -14,7 +14,7 @@
             type: git
             url: "${_param:jenkins_gerrit_url}/mk/mk-pipelines"
             branch: "${_param:jenkins_pipelines_branch}"
-            credentials: "gerrit"
+            credentials: "${_param:jenkins_gerrit_credentials}"
             script: backupninja-backup-pipeline.groovy
           param:
             SALT_MASTER_CREDENTIALS: