RFR JDK-8034057: Files.getFileStore and Files.isWritable do not work with SUBST'ed drives (win)

[Pavel Rappo]

Hi everyone,

could you please review my change for JDK-8034057: http://cr.openjdk.java.net/~alanb/8034057/webrev/

It turns out some of win32 functions don't work well with SUBSTed drives (namely GetVolumePathName). As a result it fails to create WindowsFileStore. This is a simple fallback type solution. It first tries to create WindowsFileStore the old way and if it fails with specific error, tries different approach.

Thanks
-Pavel