LU-15555 ldiskfs: large directory causes htree corruption

LU-15555 ldiskfs: large directory causes htree corruption

When creating a lot of files in a single directory, it can
get corrupted because of a typo in ext4-kill-dx-root.patch.

Lustre-change: https://review.whamcloud.com/46526
Lustre-commit: ea3ee9337f9bcd42360e4523f1e34bcd04d3bf41

Change-Id: Ia36278580741e1eb905e24a3a6231ba7daaa882a
Fixes: 20a6d32 ("LU-12637 kernel: RHEL 8.1 server support")
HPE-bug-id: LUS-10730
Signed-off-by: Andrew Perepechko <c17827@cray.com>
Signed-off-by: Alexander Zarochentsev <c17826@cray.com>
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@hpe.com>
Reviewed-on: https://review.whamcloud.com/48545
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Artem Blagodarenko <ablagodarenko@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>