LU-15278 lod: distinguish DIR/REGULAR lod_object members

LU-15278 lod: distinguish DIR/REGULAR lod_object members

In lod_striping_free_nolock(), we need to distinguish lod_object
type, since DIR/REGULAR lod_object structure share the same memory
region, it could accidently free some unintended memory if it treat
DIR lod_object as REGULAR one, or vice versa.

Lustre-change: https://review.whamcloud.com/45710
Lustre-commit: 7a9c9ccabe93f2d96c80e90f8cbb786faca74835

Fixes: 6a20bdcc608b ("LU-11376 lov: new foreign LOV format")
Fixes: fdad38781ccc ("LU-11376 lmv: new foreign LMV format")
Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Change-Id: I2d4c563725b35f7a75f0f1fbf9c1d35b1799eff4
Reviewed-by: John L. Hammond <jhammond@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/45940
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>