Security labels go with each directory entry, thus they are always
stored in the page cache, not in the head buffer.  The length of the
reply that goes in head[0] should not have changed to support
NFSv4.2 labels.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>