set waiting refresh to 20 seconds

rdgenerator/templates/waiting.html

@@ -212,7 +212,7 @@
 
         setTimeout(function() {
             window.location.replace('/check_for_file?filename={{filename}}&uuid={{uuid}}&platform={{platform}}');
-        }, 5000); // 5000 milliseconds = 5 seconds
+        }, 20000); // 20000 milliseconds = 20 seconds
     </script>
 </body>
 </html>