message: Nydusify: adjust prefetch path from absolute to relative
  Adapt the new behavior of nydus-image `--prefetch-policy` option, it accepts
  rootfs relative path instead of absolute path to specify perfetch directory
  or file list.
diff: @@ -8,7 +8,6 @@ import (
  "io"
  "os"
  "os/exec"
  - "path/filepath"
  )
  type BuilderOption struct {
  @@ -65,7 +64,6 @@ func (builder *Builder) Run(option BuilderOption) error {
  }
  if option.PrefetchDir != "" {
  - option.PrefetchDir = filepath.Join(option.RootfsPath, option.PrefetchDir)
  args = append(args, "--prefetch-policy", "fs")
  }
  