Let's suppose that I've manually modified files in .git/annex/objects,
for example I ran an rsync or some other file synchronization software
to copy files. As a result, some objects have disappeared, others have
appeared. After that `git annex whereis .' displays stale information,
it doesn't take the manual modifications to accound. `git annex fsck'
seems to fix this, but it runs the rehashing of all new files, so it's
slow. Is there a fast alternative, which notices all the object file
changes, trusts them, and just updates .git/annex/index quickly?