This would be like enabling the annex.tune.objecthashlower=true 
[[tuning]] when creating a repository, but could be done after the fact,
eg when a user needs to clone an existing reppsitory to a filesystem
that has problems with mixed case hash directories.

The adusted branch would simply convert annex links to use lower-case
hashing, which is easy. But it would also need to enable storing new object
files in lower-case hash directories, and move any currently stored object
files to those directories.

How to handle a `git checkout master` then? None of the annex links in
master would work. Normally the user can leave an adjusted branch that way,
but if they wanted to leave this one, there would have to be a command
to move everything back.

Note that, annexLocationsNonBare does fall back to looking for
hashDirLower, so getting files from a repository with this enabled to
another repository should work ok. --[[Joey]]
