Jobs reporting to treeherder should rely on the task route for project,
revision, and pushlog ID rather than things stuffed into task.extra.treeherder.
This also removes the need for a revision_hash that was calculated by mozilla-taskcluster.
MozReview-Commit-ID: EcQM9QRZzgG
--HG--
extra : rebase_source : f04f6724feef2dd51b4b98c67c9a261b093f452b
extra : amend_source : 0590605834d93359206f49edd94396c43b57f6dd