MORE Cleanup refcounting in FSAL

Signed-off-by: Frank S. Filz <ffilzlnx@mindspring.com>
fsal_filesystem: uses dev_t as the fsid when get_posix_fsid() found (0,0) as fsid for a fileystem

Signed-off-by: Philippe DENIEL <philippe.deniel@cea.fr>
FSAL_LUSTRE/fsal_file_system: adds what's needed to manage Lustre with fsal_filesystem

This commit integrates changes made after Frank and Malahal's review on github.

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

Conflicts:
	src/FSAL/FSAL_LUSTRE/export.c