As we briefly discussed via email, it would be nice if sync could sync only some branches (e.g. git-annex) not all at once.
As I suggested in email, this could be something like git annex sync --branch B
and --branch could be repeated to add other branches, with the default
being to sync them all. git annex sync --branch git-annex would need to
be special cased I think.
git annex sync --branch B
git annex sync --branch git-annex