changegroup: move node sorting into deltagroup() The 3 callers of deltagroup() all sort nodes and convert to integer revs immediately before calling deltagroup(). Stepping back a bit, aside from the constraints on node ordering that always apply (namely that a node must follow its ancestor), it makes sense for sorting to be an implementation detail of the store. Moving the sorting into deltagroup() will open the door for moving sorting into a storage API. The test for the changelog in deltagroup() to impact the sorting method is a bit hacky. I suspect this will be resolved once we establish a formal interface for delta group generation and port changelog to it. Differential Revision: https://phab.mercurial-scm.org/D4224