title: Make Firefox forget a site was https
body: <p>I do a bunch of testing of web server setups, and so I frequently change a given virtual host's default protocol from <code>http</code> to <code>https</code> and back. </p>
  
  <p>Unfortunately, Firefox keeps remembering that a site used to be <code>https</code> and refuses to reconnect to it with <code>http</code>, at least for some after the last 
  connection. </p>
  
  <p>Is there a setting, or some stored value somewhere where I can make Firefox forget that it has ever seen this site before? I looked all over <code>about.config</code> and in the settings (I was looking for something rather similar to the "forget cookies" dialog) but came up empty.</p>