Updates number of credits not working when credit is added with discount

Problem/Motivation

Updates number of credits a user has based on his order is not working correctly when credits are added to bonus products with discount.

Steps to reproduce

Add new discount with rule when buying 1 credit get 1 extra for free.
Buy 1 credit.
Summary of credits on accounts is 1 instead of 2.

Proposed resolution

Add another line item type to commerce_credits_rules_action_update_on_checkout
Credit added with discount has type of product_discount not just product.