LU-10785 llite: use xattr_handler name for ACLs

LU-10785 llite: use xattr_handler name for ACLs

If struct xattr_handler has a name member then use it (rather than
prefix) for the ACL xattrs. This avoids a bug where ACL operations
failed for some kernels.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I28f6c5dbe3cdc4155e93d388d2c413092e02c082
Reviewed-on: https://review.whamcloud.com/31595
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>