LU-17557 osd: only accounting inodes are special

LU-17557 osd: only accounting inodes are special

don't treat all inodes special (system) because 5.14 turns filesystem
read-only when we try to access an non-existing inode with
LDISKFS_IGET_SPECIAL flag.

Fixes: 2c0b2b7540 ("LU-13166 osd-ldiskfs: fix to allow to get system inode")
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I0c05adaf7b94e04c094cb069e8271bf478010b8c
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/54091
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Li Dongyang <dongyangli@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>