Concession change bug

[evanschris]

If a concession was changed after it had been selected - it would either not register this change, or had the potential to add multiple passes of each type even though you have only one selected due to the change.

bug quick fix - For a quick fix for now once a pass is selected I have disabled the chosen dropdown - if the user wants to change it to a different concession they would have to remove it using the delete button then add another one. Its not perfect, but it works well enough for now by removing the chance of anyone falling into that bug.