A top-level .noannex file will prevent git-annex init from being used in a
repository. This is useful for repositories that have a policy reason not
to use git-annex. The content of the file will be displayed to the user who
tries to run git-annex init.
This also affects git annex reinit and initialization via the webapp.
It does not affect automatic inits, when there's a sibling git-annex branch
already.
This commit was supported by the NSF-funded DataLad project.
