braintree/braintree_ruby — pull request #30 by dmathieu (2012-10-23 15:18:50+00:00)
Title: allow a query parameter with no value

If, for some reason, the after request gets parameters with no value. eg:

/after_payment?http_status=200&id=rmvv3pzx77pmgsvv&kind=create_payment_method&vat_number=&hash=e4b312bc2aa5f77a85e22cb796fbc5c59d67410f

Here, the `vat_number` parameter is present, but has no value (or a blank one).
This currently fails, as the library tries to get the value but can't unescape nil.

This replaces the nil value by a blank value, therefore not removing the key, but not failing either because it' can't be escaped.