FSAL_VFS: implement correct support for system.posix_acl_access attr.
pNFS/LUSTRE: invalidate attrs on close (force DS/MDS coherency). Think about something more subtle.
SQUASH ME

Signed-off-by: Philippe DENIEL <philippe.deniel@cea.fr>
This commits implements "extended group lists" feature which
allows secondary group list to be longer than 16 by not trusting grplist in AUTH_SYS creds

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