Remove unused parameter in xtrabackup job

Change-Id: I5167516357c0b795740bfc4f7a1a875003dc4389
Releated: PROD-28768(PROD:28768)
diff --git a/jenkins/client/job/deploy/galera_database_backup.yml b/jenkins/client/job/deploy/galera_database_backup.yml
index e78c29b..1cb96a8 100644
--- a/jenkins/client/job/deploy/galera_database_backup.yml
+++ b/jenkins/client/job/deploy/galera_database_backup.yml
@@ -26,8 +26,5 @@
             SALT_MASTER_URL:
               type: string
               default: "${_param:jenkins_salt_api_url}"
-            ASK_CONFIRMATION:
-              type: boolean
-              default: 'true'
           triggers:
             - timed: "${_param:backup_min} ${_param:backup_hour} ${_param:backup_day_of_month} ${_param:backup_month} ${_param:backup_day_of_week}"