FSAL_LUSTRE: adds missing prototype in lustre_methods.h

Signed-off-by: Philippe DENIEL <philippe.deniel@cea.fr>
config_parsing: adds CONF_MAND_ macros for INET_PORT and IPV4_ADDR.
Those macros are required for correct tuning of pNFS in FSAL_LUSTRE.

Signed-off-by: Philippe DENIEL <philippe.deniel@cea.fr>
FSAL_LUSTRE: makes pnfs parameter for LUSTRE part of export parameter

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