streamclone: move applystreamclone() from localrepo.py Upcoming patches will modernize the streaming clone code. Streaming clone data and code kind of lives in its own world. exchange.py is arguably the most appropriate existing location for it. However, over a dozen patches from now it became apparent that there was a lot of code related to streaming clones and that having it contained within its own module would make it easier to comprehend. So, we establish streamclone.py. It's worth noting that streamclone.py existed a long time ago, last seen in the 1.6 release. It was removed in 04f76a954842. The function was renamed as part of the move because its old name was redundant with the new module name. The only other content change was "self" was renamed to "repo" and minor grammar in the docstring was updated.