Mock the bare minimum of a project's exp.json to get UrlUtils test passing
Mock the bare minimum of a project's exp.json to get UrlUtils test passing

UrlUtils has a test to get the URL of a bundle it's about to publish. This now reads from exp.json so we need to mock it out.

UrlUtils tests (all XDL tests) are passing.

fbshipit-source-id: d6960af

exponentjs/xdl,exponentjs/xdl,exponentjs/xdl