title: I can't delete the folder generated/code in Magento 2.2.6
body: <p>I use Docker for my project. After installing the 2.2.6 package with sample data, it gives me problems like the following when I execute <code>php bin/magento cache:clean</code></p>
  
  <blockquote>
    <p>The file "/var/www/html/src/generated/code/Magento/Backend/App/Request/PathInfoProcessor/Proxy.php" cannot be deleted Warning!unlink(/var/www/html/src/generated/code/Magento/Backend/App/Request/PathInfoProcessor/Proxy.php): 
    No such file or directory</p>
  </blockquote>
  
  <p>The <code>generated/code</code> folder can not be deleted and I have to restart my computer then it does let me delete the folder</p>
  
  <p>I use php 7.1.22 , percona 5.6.39 and docker Version 18.06.1-ce-win73 (19507)</p>