title: change shutdown sequence to avoid nfs umount failure
body: <p>I am running strain of raspbian (debian-based) on my Raspberry Pi, and during reboots, the device seems to hang on shutdown while trying to unmount an NFS directory...</p>
  
  <pre><code>....
  [ok] Stopping Network connection manager: wcid.
  .....
  [[timestamp]] nfs: server freenas not responding, still trying
  </code></pre>
  
  <p>Looks to me like its waiting for a response from NFS despite already having stopped networking on the device. This will hang for 5 minutes or sometimes until I unplug it (i've waited as much as 30 minutes)</p>
  
  <p>Is there a way to reorder this shutdown sequence so this doesn't happen?</p>