staging: lustre: remove Size on MDS support

Remove unused definitions related to Size on MDS support from
lustre/include/lustre/lustre_idl.h. Remove unused code from several
places in lustre/.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6047
Reviewed-on: http://review.whamcloud.com/13443


Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>