config.ru: fix integration with Killbill

Update to latest framework APIs.

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
Jarfile: add javax.servlet:javax.servlet-api 3.0.1

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
test: fix tests after recent API changes

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>