CoreOS: why still get reboot message after disabling reboot strategy?

I am still getting this.

$ vagrant ssh

...

CoreOS stable (681.2.0)

Broadcast message from locksmithd at 2015-07-23 23:41:12.013908559 +0000 Local 
System reboot in 5 minutes!

      

        
        
        
      

    

But I've already disabled it.

$ cat user-data.in
#cloud-config
---
coreos:
  update:
    reboot-strategy: off

      

        
        
        
      

    

Also inside,

$ cat /etc/coreos/update.conf
GROUP=stable
REBOOT_STRATEGY=off

      

        
        
        
      

    

So why is it still rebooting? Any other place to turn it off? Thank you so much for your help.