Fix bug that lost modifications to unlocked files when init is re-ran in an
already initialized repo.
In retrospect needing scanUnlockedFiles False in the direct mode upgrade
path was a good hint that it was unsafe when used with True.
However, this bug did not affect upgrade from v5. In such an upgrade, an
unlocked file that is modified is left as-is. The only place
scanUnlockedFiles True did overwrite modified unlocked files is during an
git-annex init of a repo that was already initialized by git-annex.
(I also tried a scenario where the repo had not been initialized by
git-annex yet, but was cloned from a v7 repo with an unlocked file, and the
pointer file replaced with some other content, and the data loss did not
occur in that situation.)
Since the fixed scanUnlockedFiles avoids overwriting non-pointer files,
it should be safe to run in any situation, so there's no need any longer
for the parameter.
git-annex allows managing files with git, without checking the file
contents into git. While that may seem paradoxical, it is useful when
dealing with files larger than git can currently easily handle, whether due
to limitations in memory, checksumming time, or disk space.
For documentation, see doc/ or <https://git-annex.branchable.com/>
e2d4c133f5