changegroup: inline ellipsisdata() There's only one caller of it. I don't think it needs to exist as a standalone function. Differential Revision: https://phab.mercurial-scm.org/D4074

changegroup: rename "revlog" variables "revlog" shadows the module import. But more importantly, changegroup generation should be storage agnostic and not assume the existence of revlogs. Let's rename the thing providing revision storage to "store" to reflect this ideal property. Differential Revision: https://phab.mercurial-scm.org/D4073