It's possible that a temporary directory can be created on a different
mount, and when moved during a clone, creates an I/O error.
To prevent this, add a method to `Storage` which creates a temporary
directory and `Repository` with the path in the form
`<rid>.lock`.
This `.lock` path name can easily be skipped when listing
repositories. Further tooling can be added for detecting leftover
`.lock` directories if, for some reason, they were not cleaned up by
the `tempfile` crate.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
e71f07e592