title: Symfony2 in_memory users provider issue
body: <p>I have a Symfony2 application that loads users from <code>in_memory</code> user provider. The <code>security.yml</code> is the following:</p>
  
  <pre class="lang-yaml prettyprint-override"><code>security:
      encoders:
          Symfony\Component\Security\Core\User\User: plaintext
  
      role_hierarchy:
          ROLE_ADMIN:       ROLE_USER
          ROLE_SUPER_ADMIN: [ROLE_USER, ROLE_ADMIN, ROLE_ALLOWED_TO_SWITCH]
  
      providers:
          in_memory:
              users:
                  admin: { password: mypassword, roles: [ 'ROLE_ADMIN' ] }
  
      firewalls:
          dev:
              pattern:  ^/(_(profiler|wdt)|css|images|js)/
              security: false
  
          login:
              pattern:  ^/demo/secured/login$
              security: false
  
          secured_area:
              pattern:    ^/
              anonymous: ~
              http_basic:
                  realm: "MyApp Realm - Login"
  
      access_control:
          #- { path: ^/login, roles: IS_AUTHENTICATED_ANONYMOUSLY, requires_channel: https }
          #- { path: ^/_internal, roles: IS_AUTHENTICATED_ANONYMOUSLY, ip: 127.0.0.1 }
          - { path: ^/subscription/show, roles: ROLE_ADMIN }
          - { path: ^/send, roles: ROLE_ADMIN }
  </code></pre>
  
  <p>In my local development environment (a Mac Book Pro) this configuration works as expected. When I go to routes <code>_/send_</code> or <code>_/subscription/show_</code>, Symfony asks me for login and if I enter credentials <em>admin</em> and <em>mypassword</em> I can view pages correctly.</p>
  
  <p>But in <em>production</em> environment (a Debian server) I have to perform login to see that routes but the same username and password doesn't work! The HTTP basic authentication login prompt never go away! I can't understand.</p>
  
  <p>Why that configuration doesn't work? And overall why in my local environment it works and in the production environment it doesn't?</p>
  
  <p>I also see a question I suppose it is related to: <a href="https://stackoverflow.com/questions/11908861/symfony2-plaintext-users-dont-work">Symfony2 plaintext users don&#39;t work</a>.
  I already tried all suggestions listed there but any of them solve the problem.</p>