Go 1.9 (golang/go@66b5a2f) removed file type bits from
archive/tar.FileInfoHeader().
This commit ensures file type bits are filled even on Go 1.9 for
compatibility.
Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Upstream-commit: 1a451d9a7bb9cd7d437b42d4e73b0560fbf84348
Component: engine