opencart/opencart — pull request #2434 by Dreamvention (2014-12-04 20:01:55+00:00)
Title: Update tax.php

this will remove the notice when the array $this->session->data['payment_address'] exists but $this->session->data['payment_address']['zone_id'] doesn't

since module may add $this->session->data['payment_address'] without zone_id - we need to check it first