Summary: Rename ClientDevice to DummyDevice. It is being currently used in the case when we do cert exchange through WWW/Distillery. In this mode we are not able to figure out the exact device id(instead we create a fake one) and thus we would not like to use Android or IOSDevice for such cases. Reviewed By: mweststrate Differential Revision: D26944415 fbshipit-source-id: f9f76e8997cf5402ba5627ae1959f5a11e078bb1