title: docker login fails on a server with no X11 installed
body: <p>I am trying to deploy a docker configuration with images on a private docker registry.</p>
  <p>Now, every time I execute <code>docker login registry.example.com</code>, I get the following error message:</p>
  <blockquote>
  <p>error getting credentials - err: exit status 1, out: <code>Cannot autolaunch D-Bus without X11 $DISPLAY</code></p>
  </blockquote>
  <p>The only solution I found for non-MacOS users was to run <code>export $(dbus-launch)</code> first, but that did not change anything.</p>
  <p>I am running Ubuntu Server and tried with both the Ubuntu Docker package and the Docker-CE package.</p>
  <p>How can I log in without an X11 session?</p>