HOTFIX 2015.5 2015.6 - Fixed issue where the wrong cart could be loaded

We fixed an issue where the wrong cart could be loaded when logging in if the customer had used more than one cart during that day.

Scenario: user A adds item X to cart and logs into customer account. Then, in the same day, user B adds item Y to cart and logs into same customer account. User A adds item Z to cart so his cart now contains item X and item Z. User B's cart still contains only item Y. User C then logs into the same customer account. Prior to this fix his cart would contain only item Y. Now, as expected, it pulls the most recently altered cart so it will load item X and item Z.