Windows: FILE_FS_DEVICE_INFORMATION Device Type

Consistently report our device type as FILE_DEVICE_NETWORK_FILE_SYSTEM
instead of FILE_DEVICE_DISK or FILE_DEVICE_DISK_FILE_SYSTEM except
when returning FILE_FS_DEVICE_INFORMATION where we must lie and state
that the device type is FILE_DEVICE_DISK.  Otherwise, the Win32 API
GetFileType() returns FILE_TYPE_UNKNOWN instead of FILE_TYPE_DISK.

Applications built from msys (but not current cygwin) treat files
of type FILE_TYPE_UNKNOWN as special character devices instead of
files.  This breaks msysGit.

Change-Id: I7107ae84ede31abb01481b2e8c3915588d9fd529
Reviewed-on: http://gerrit.openafs.org/8973
Reviewed-by: Rod Widdowson <rdw@steadingsoftware.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>