* sync: When --quiet is used, run git commit, push, and pull without
their ususual output.
* merge: When --quiet is used, run git merge without its usual output.
This might also make --quiet work better for some other commands
that make commits, like git-annex adjust.
Sponsored-by: Kevin Mueller on Patreon
Rather than direct mode, which this is a small step on the path to
removing.
Init on a crippled filesystem already used v7 adjusted branches,
and like that, this doesn't pose any interoperability issues with old
versions of git-annex that clone the same repo, because files are only
unlocked on the adjusted branch.
