remotefilelog: remove some BC code related to streamclone Since remotefilelog is now moved to core and we have streamclone._walkstreamfiles() in core, we don't need to have the backward compatibility code. People with old mercurial version should use remotefilelog from hg-experimental repo as IMO remotefilelog will go under a good refactoring and old clients will break. # no-check-commit foo_bar function name Differential Revision: https://phab.mercurial-scm.org/D5189

remotefilelog: add some docstring Differential Revision: https://phab.mercurial-scm.org/D5131

remotefilelog: rename wireproto methods and remaining capabilities This is a mess, in part because there should be more constants throughout. I know we typically do exp- instead of the x_ business in this change, but I also had to use this in some function names, so I figured until I can break that coupling I'd go with this. If it's too unpleasant during review, let me know and I can probably clean it up some more. # no-check-commit due to new foo_bar naming - too hard to avoid right now :( Differential Revision: https://phab.mercurial-scm.org/D5129

remotefilelog: consolidate and rename on-disk store requirement The value of this constant appeared in too many places. While we're here, rename it to be more consistent with our naming conventions for experimental functionality. Differential Revision: https://phab.mercurial-scm.org/D5128

remotefilelog: consolidate and rename bundle2 capability Bonus: we catch a spot where the shallowrepo requirement was being misused as the bundle2 capability. Differential Revision: https://phab.mercurial-scm.org/D5127

remotefilelog: rename capability for legacy ssh file fetching method I think I want to delete this, but for now we'll just rename this so it's easy to tell apart from other strings that have the same value. Differential Revision: https://phab.mercurial-scm.org/D5126