Link store credit to account on checkout is not working

[jogit82]

When someone checked the checkbox that says SAVE to link the remaining balance of their store credit to their account, it is not linking.
Repro:
go through checkout process
under store credit section, apply a store credit code
do not use all the credits, have some remainder
then choose add remainder to account(SAVE)
go through checkout
land on order confirmation
go to my account
store credit is not linked.

found possible fix:
line 1051 models-checkout.js
the error was undefined 'credit.code'
return credit.attributes.code.toLowerCase() === creditCode.toLowerCase();
** This solved the issue

*I tried return credit.get('code').toLowerCase() === creditCode.toLowerCase();
*Does not work