nfs4 op read/write: trivial fix - use the correct value for max read/write size

Signed-off-by: Philippe DENIEL <philippe.deniel@cea.fr>
HPSS FSAL build, set rpath and link ganesha.nfsd against hpss (it won't setup properly otherwise)
Also, remove no longer needed files

Signed-off-by: Philippe DENIEL <philippe.deniel@cea.fr>