title: pagination suffix doesn't work on previous links
body: <p>hi this in my pagination code</p>
  
  <pre><code>$config['base_url']    = base_url().'cp/orders/';
  $config['suffix'] = '?'.http_build_query($_GET, '', "&amp;");
  $config['uri_segment'] = 3;
  $config['total_rows']  = $count_all;
  $config['per_page']    = 20 ;
  $this-&gt;pagination-&gt;initialize($config);
  echo $this-&gt;pagination-&gt;create_links();
  </code></pre>
  
  <p>so in the first page it works fine when i click on page2 it goes to </p>
  
  <pre><code>http://mysite.com/cp/orders/20?sort=id&amp;adc=desc
  </code></pre>
  
  <p>but in the second page if i click on page one or previous page ( &lt; ) it goes to </p>
  
  <pre><code>http://mysite.com/cp/orders/20
  </code></pre>
  
  <p>this</p>
  
  <pre><code>$config['suffix'] = '?'.http_build_query($_GET, '', "&amp;");
  </code></pre>
  
  <p>doesn't work in the previous  links! </p>