LU-17546 osd: use __vfs_removexattr

LU-17546 osd: use __vfs_removexattr

as otherwise vfs_removexattr() taking inode's lock confict with
osd_execute_truncate() while we don't really need inode's lock
because another per-object lock has been already taken.

Fixes: dcd5607ce0 ("LU-13430 vfs: add ll_vfs_getxattr/ll_vfs_setxattr compat macro")
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I43c1c60d2a9f911b6395e1b7546507074a90b1cf
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/54072
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>