Manage pNFS Data Servers

* Parallels export manager.
* Moved DS handle creation to pDS ops vector (and *ds.c files).
* Added FSAL op for creation of subsequent pDS ops vectors.
* Added pDS op for creation of subsequent DS handle ops vectors.
* Added pDS op for updating permissions (regardless of export).

+ FSAL_CEPH with minimal support, requires DS {} configuration.
+ FSAL_GPFS manages DS {} at same time as EXPORT {}.
+ FSAL_LUSTRE manages DS {} at same time as EXPORT {}.
-- include circular dependency exposed!

- Merged static one-time-use functions in FSAL/commonlib.c
- Provided default pDS creation/destruction in FSAL/default_methods.c
  (unlike exports).
- Increase refcount size to 64 bits for DS handles, matching others.
- Related minor field/function renaming.

Bug fix: in PutFH, put before get, then comparing old id, could cause
use of dereferenced data.  Always get (inc) new before put (dec) old.

Bug fix: in PutFH, fh_desc.addr should have pointer to data
(match DS side with export side).

Bug fix: missing glist_init() in fsal_pnfs_ds_init()

Bug fix: wrong macro list element in shutdown_pnfs_ds() --
motivating field rename.

Signed-off-by: William Allen Simpson <bill@cohortfs.com>
Acked-by: Frank S. Filz <ffilzlnx@mindspring.com>

Fix FSAL_LUSTRE to compile.
-- brute force move of internal.h structures to methods.h
-- (should probably be split between them)
Signed-off-by: Frank S. Filz <ffilzlnx@mindspring.com>
UPDATE - Manage pNFS Data Servers

This patch should be squashed with the previous patch to allow proper
compilation and proper bisectability.

Updates:

Fix FSAL_LUSTRE to compile

Make sure fsal_pnfs_ds object is saved/restored with SAVEFH/RESTOREFH with
proper refcounting.

If DS is associated with an export (DS "number" equals export_id), do all the
export permissions checking in PUTFH.

If DS is associated with an export, indicate so in the fsal_pnfs_ds
object. This is done for FSAL_GPFS and FSAL_LUSTRE.

Signed-off-by: Frank S. Filz <ffilzlnx@mindspring.com>

Conflicts:
	src/FSAL/FSAL_LUSTRE/lustre_methods.h
	src/include/fsal_api.h
	src/support/ds.c