title: Unserialize error opencart 2.1.0.1
body: <p>Im getting this error in the error log on opencart 2.1.0.1</p>
  
  <pre><code>PHP Notice:  unserialize(): Error at offset 0 of 2 bytes in /home/zachovek/public_html/vqmod/vqcache/vq2-catalog_controller_module_d_quickcheckout.php on line 1392
  </code></pre>
  
  <p>When the customer is placing an order via quickcheckout and at the same time is registering new profile - this error appears BUT NOT ONLY - the products in the order are not showing! This is the following line of the code:</p>
  
  <pre><code>$data['custom_field'] = unserialize($customer_info['custom_field']);
  </code></pre>
  
  <p>How can i fix it? 
  Thank you!</p>