title: Docker building fails randomly with Error mounting
body: <p>Every time I try building with docker or fig an image (doesn't matter which one), I randomly will get </p>
  
  <pre><code>Cannot start container &lt;containerId&gt;: Error getting container &lt;containerId&gt; from driver devicemapper: Error mounting '/dev/mapper/docker-8:1-262151-&lt;containerId&gt;' on '/var/lib/docker/devicemapper/mnt/&lt;containerId&gt;': no such file or directory
  </code></pre>
  
  <p>Weird thing is, if I re-run it, it usually won't have the same error.</p>
  
  <p>Note that I am running docker inside vagrant (ubuntu-trusty-64)</p>