push: update push logic to match mercurial upstream Commit e10000369b47 in upstream Mercurial changed the checkpush function signature. So we need to update hgsubversion accordingly. Ran the tests against the tip of the hg repo, against a version of hg from January before the exchange module, and against a version of hg after pushoperations was added but before checkpush used it, and the tests passed in all cases.