Issue with 'after_menu' argument in 'addons'

Similar to #2335

The 'after_menu' argument is being outputted after the loop (In multiple
mode) while the 'before_menu' is being outputted in the loop. This means
if you have multiple addons and these arguments set then you
will output more "befores" than "afters".

This change fixes the issue.
Merge pull request #2393 from WazzaJB/master

Render after_menu markup correctly in product.addons (with multiple addon menus) props WazzaJB