debugformat: update label depending on value difference The new label highlight areas where the repo format differs from current config or default. This should help people spot area where a repository mismatch with the expected state.

debugformat: add data about the config when verbose In verbose mode, the command also displays the current configuration choice for the variant and the global Mercurial default for it.

debugformat: add a 'debugformat' command The command displays basic data about all format variants registered for repo upgrades. This gives a quick way to peek into a repository format. The 'fm.write()' calls are very independent because more data will be added in later changeset. Having more separate call make the later patch clearer.

upgrade: rename 'removecldeltachain' to 'plain-cl-delta' The new naming is more descriptive of a "state" while the older one was more about "action". I'm looking into command exposing more of data about the state of the repository so "state" oriented work better there. The key has not been made public anywhere outside the debug area so it is fine to update it.

tests: glob away ' that doesn't occur on all platforms in lfs test Differential Revision: https://phab.mercurial-scm.org/D1623

rebase: extract _assignworkingcopy Slightly cleaner, and makes it easier to hook this in an extension. Differential Revision: https://phab.mercurial-scm.org/D1617