- fixes about removing lmv_obj when coresponding inode is getting removed. Former

- fixes about removing lmv_obj when coresponding inode is getting removed. Former
implementation was buggy and did not take into account the case when inode is just
released due to memory pressure and only removed lmv_obj when inode was deleted.
Current implementation is much better especially if some client will produce lots
of splitted dirs.

- cleanups struct lmv_obj. Renames in lmv obj manager to make names shorter.

- making lmv_obj manager to use kmem cache for struct lmv_obj instances. This
should work faster if some client will produce lots of splitted dirs.

- fix in lmv_connect(). It should not remove lmv_proc_dir if thereis no error.

- added some asserts. Fixes in lmv_obj manager to make it working correct if
an object is getting removed by lmv_delete_obj().

- removed error message when lmv_put_inode() detects, that object is still used by
someone, removed redundant assignments and variables. Cleanups about using lustre_id
in lmv_obj manager.

- cleanups about ENTRY/RETURN things in lmv object manager.