fix many bugs that prevented previously-mounted filesystems from

fix many bugs that prevented previously-mounted filesystems from
mounting a second time:
 - set the oscc_next_id (via obd_setattr) before we use that value to
   recover orphans
 - when recovering orphans, send the actual last-used ID (oscc_next_id - 1),
   instead of oscc_next_id
 - in filter_destroy_precreated, call filter_destroy with a NULL oti
   to avoid saving locks for the reply-ack
 - remove the boot count component of the filter objid; it is no
   longer required and makes orphan recovery harder
 - start the filter objid count at 1
 - orphan recovery is a dangerous process which if done incorrectly
   will delete the wrong objects; with that in mind, we now call a
   dramatically simpler lov_create_orphans() instead of the normal
   out-of-control lov_create