title: Aurora MySql Default USAGE privileges on every newly created user
body: <p>It seems that when creating a new user, a default &quot;USAGE&quot; privilege is granted on EVERY database without any way to revoke these &quot;usage&quot; privileges.</p>
  <p>steps to reproduce:</p>
  <pre><code>CREATE USER 'mynewuser'@'%' 
  IDENTIFIED BY 'xxx';
  flush privileges;
  </code></pre>
  <p>then</p>
  <pre><code>SHOW GRANTS FOR 'mynewuser';
  &gt;    GRANT USAGE ON *.* TO 'mynewuser'@'%'
  </code></pre>
  <p>Trying to revoke:</p>
  <pre><code>REVOKE USAGE ON *.* FROM 'mynewuser'@'%';
  FLUSH PRIVILEGES;
  SHOW GRANTS FOR 'mynewuser';
  &gt;    GRANT USAGE ON *.* TO 'mynewuser'@'%'
  </code></pre>