title: Mount is not showing up when it is defined in cloud-config.yaml
body: <p>I am new to CoreOS and trying to mount an attached external HD on startup. I am using cloud-config to setup my machine, and my cloud-config.yaml file looks like this.</p>
  
  <pre><code>#cloud-config
  
  # include one or more SSH public keys
  ssh_authorized_keys:
    - ssh-rsa xxxxxx
  
  coreos:
    units:
      - name: media-data.mount
        command: start
        content: |
          [Mount]
          What=/dev/md126
          Where=/media/data
          Type=ext4
  </code></pre>
  
  <p>Why is my mount not showing up in /media/data? When I create an empty directory in /media/data and mount using</p>
  
  <pre><code>mount /dev/md126 /media/data 
  </code></pre>
  
  <p>I am succesfully able to access the data stored on the external HD.</p>