Added files properties are ignored for SVN local repositories with backslash as path separator on Windows (e.g. file:///C:\repo\path)

While such URLs are not really compliant with RFC1738 some users might want to provide them, so I guess we should normalize them to slash-separated form.

Currently providing such a URL will lead to problems indexing properties (e.g. binary flag) for added files (see FE-5585 for similar issue).