LU-11739 lod: subdir under ROOT should honor default layout

LU-11739 lod: subdir under ROOT should honor default layout

Though sub directories under ROOT don't inherit ROOT default
layout, they should hornor ROOT default layout in creation.

Add sub test in sanity.sh 65n to verify this.

Fixes: 0a988cae95 ("LU-11739 lod: don't inherit default
                    layout from root directory")

Lustre-change: https://review.whamcloud.com/35204
Lustre-commit: 693fb63ac777eab426f1b618316a5649534759ad

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: I1edf91da7944a8871652df7bca2104d00f66163a
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Signed-off-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/36370
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>