remove unused keyword arg data to prevent 500

Fixes http://manage.dimagi.com/default.asp?96722 (stack trace: https://preview.commcarehq.org/couchlog/view/e0fb23a0115a106a5e8330d454f2f0f3/)

Before the POST data was being passed to the data keyword argument.  Since data is never initialized as a keyword arg I'm removing it