title: Symfony / FOSuserBundle : salt are null?
body: <p>I'm using :</p>
  
  <ul>
  <li>Symfony 3.4</li>
  <li>FOSUserBundle 2</li>
  </ul>
  
  <p>FOSuserbundle is well installed and works like a charm. I noticed that in my database, in the users table, the column "salt" is always empty :</p>
  
  <p><a href="https://i.stack.imgur.com/LqeWv.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LqeWv.jpg" alt="enter image description here"></a></p>
  
  <p>Below is an extract from my security.yml file :</p>
  
  <pre><code>security:
      encoders:
          FOS\UserBundle\Model\UserInterface: bcrypt
  </code></pre>
  
  <p>For the record, I added the 2 users with the command "fos:user:create".</p>
  
  <p>Is this normal ?</p>