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.