LU-15300 mdt: refresh LOVEA with LL granted

LU-15300 mdt: refresh LOVEA with LL granted

this change tries to fix two problems:
1) mdt_reint_open() fetches LOVEA before layout lock is taken.
   this may race with another process changing the layout and
   may result in a stale layout returned with a granted layout
   lock - re-fetch LOVEA once layout lock is granted

2) lov_layout_change() should not apply old layouts which
   can get through when MDS doesn't take layout lock

3) LFSCK shouldn't ignore layout version stored on MDS to avoid
   a situation when version degrades compared to client's copy.

This patch misses an optimization and can result in a number of
useless calls to OSD to fetch LOVEA. To be fixed in a followup
patch.

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: Idee1101d152ab09947faf6d75574a8761a7690a5