- setting owner/group on OSS (needed for quotas)

- some fixes:
  - deadlock on soc client lock.
  - idr_remove() issue.
  - forwarding to wrong MDS in lmv_link()
  - f_dput(dentry) before using it in filter_lvbo_update()
  - filter_sync() assert(group > 0) due to missed GROUP flag oa->o_valid in ll_fsync().
  - cleanups, comments and more debugging messages.
  - jump to wrong label in mds_create_objects() on error path.
  - few missed/wrong ENTRY/RETURN things