* origin/pr/316:
storage/reflink: trivial style tweaks
storage/reflink: comment on _get_size() use in start()
storage/reflink: don't bother using _get_size() in create()
storage/reflink: delete all images at beginning of create()
storage/reflink: get VM dir from less arbitrary-looking path
storage/reflink: factor out _remove_all_images()
storage/reflink: _remove_incomplete_{files -> images}()
storage/reflink: omit redundant comment