title: Airflow Revision already exists
body: <p>I have ran airflow initdb for the second time and received the following error:</p>
  
  <pre><code>alembic.util.exc.CommandError: Can't locate revision identified by '9635ae0956e7'
  </code></pre>
  
  <p>So I understand that I need to remove the already registered version, but I cannot seem to find it. when I open the mysql cli (using sudo mysql) I only see 4 dbs: information_schema ,mysql, performance_schem, sys                </p>
  
  <p>How to do I remove this revision and start fresh?</p>