remotenames: rename related file and storage dir to logexchange This patch renames remotenames.py to logexchange.py, test-remotenames.t to test-logexchange.t. Also this patch renames the directory in which the data is stored from remotenames to logexchange. After this patch, data about bookmarks and branches from a server we pull is stored in `.hg/logexchange/(bookmarks|branches)` files. Thanks to smf for the suggestion. Differential Revision: https://phab.mercurial-scm.org/D1607

lfs: allow to run 'debugupgraderepo' on repo with largefiles The extensions wrap the necessary function to ensure the 'lfs' requirements won't be dropped. It is now possible to run `hg debugupgraderepo` on a repository with lfs.