Use the ocfs2_xattr_bucket abstraction in
ocfs2_xattr_create_index_block() and its helpers. We get more efficient
reads, a lot less buffer_head munging, and nicer code to boot. While
we're at it, ocfs2_xattr_update_xattr_search() becomes void.
Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>