Product count can be confusion when applying a Discount Coupon

Problem/Motivation

Number of products count in ajax driven mini cart can be confusing when using coupons since coupons are counted as a real product.

Proposed resolution

I propose a simple patch to uc_ajax_cart.module by checking if uc_coupon module is in use and not taking into accounts product from that module:

at line 289 from:

$total += $display_item['#total']; 

to:

$num = (module_exists("uc_coupon") && $display_item["module"]["#value"] == "uc_coupon") ? 0 : $display_item['qty']['#default_value'];
$total_items += $num;

This should be enaugh to resolve the total product number ambiguity.

Remaining tasks

Please evaluate it this modification is in the scope of the module and if so review it.