LU-2744 build: fix 'data race condition' issues

LU-2744 build: fix 'data race condition' issues

Fix 'data race condition' defects found by Coverity version
6.5.0:
Data race condition (MISSING_LOCK)
Accessing variable without holding lock. Elsewhere,
this variable is accessed with lock held.

Signed-off-by: Sebastien Buisson <sebastien.buisson@bull.net>
Change-Id: Ia9bad7782b6289e84c11e7998957c732508e10a5
Reviewed-on: http://review.whamcloud.com/6567
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Liang Zhen <liang.zhen@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>