LU-2285 osp: Send correct object IDs when deleting orphans

LU-2285 osp: Send correct object IDs when deleting orphans

When processing an orphan deletion request with object ID n, ofd (as
well as obdfilter in older branches) destroys objects from n + 1.
This patch fixes osp to send last used IDs instead of last used ID
plus ones, so that the first orphan in each sequence will be destroyed
correctly.

Change-Id: I6aae73dfdd7fa73aca7b1a8cfe074a1902ad981f
Signed-off-by: Li Wei <wei.g.li@intel.com>
Reviewed-on: http://review.whamcloud.com/4511
Tested-by: Hudson
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>