Making generated route objects package private

Summary: As per the discussion on the task: https://app.asana.com/0/14467453107752/15437260249194/f , made the route objects package private in spragger

Test Plan: Tested by using this updated spragger jar to generate spray server apis in sdmain codebase

Reviewers: kt, j

Reviewed By: j

Differential Revision: http://phabricator.scale-data.com/D1194