set to 06:00 and remove file glob

tasks/backup.yml

@@ -17,6 +17,6 @@
 - name: add backup cleanup cronjob
   cron:
     name: mongodb backup cleanup
-    job: 'find /opt/mongodbbackup/* -mtime +{{ mongodb.backup.keep_days - 1 }} -type f -exec rm {} \;'
-    minute: "17"
-    hour: "12"
+    job: 'find /opt/mongodbbackup/ -mtime +{{ mongodb.backup.keep_days - 1 }} -type f -exec rm {} \;'
+    minute: "0"
+    hour: "6"