Fixing error related to output produced before the headers were sent

Deleted extra lines in admin-screen.php to prevent an error: 

<code>Warning: Cannot modify header information - headers already sent by (output started at /home/surpavwe/public_html/surpassdemos.com/nineteen/wp-content/plugins/wooproduct-showcase/admin/admin-screen.php:261) in /home/surpavwe/public_html/surpassdemos.com/nineteen/wp-content/plugins/woocommerce/classes/class-wc-session-handler.php on line 63</code>