title: QSettings how to read ini without value of keys
body: <p>I have config:</p>
  
  <pre><code>[Users]
  joe
  bill
  dona
  serg
  </code></pre>
  
  <p>I need <code>QStringList</code> with all usernames.</p>
  
  <pre><code>QSettings ini("/tmp/users.ini", QSettings::NativeFormat);
  ini.beginGroup("Users");
  QStringList keys = ini.allKeys();
  qDebug() &lt;&lt; keys;
  ini.endGroup();
  </code></pre>
  
  <p>This not work :(</p>