title: Fatal error: Call to undefined method CI_Session::sess_destroy() 1.7.2
body: <p>My current version of ci is 1.7.2 but ehen i am using </p>
  
  <pre><code>            $this-&gt;session-&gt;unset_userdata('uid');
              $this-&gt;session-&gt;unset_userdata('email');
              $this-&gt;session-&gt;sess_destroy();
  </code></pre>
  
  <p>in my controller an below shown is my class controller</p>
  
  <pre><code>      function Account()
  {
      parent::BEV_Controller();   
      $this-&gt;load-&gt;model('facebook_model');
      $this-&gt;load-&gt;library('session');
      $this-&gt;form_validation-&gt;set_error_delimiters('&lt;div class="error"&gt;', '&lt;/div&gt;');
  }
  </code></pre>