LU-7232 statahead: lock leaks if statahead file recreated

LU-7232 statahead: lock leaks if statahead file recreated

During statahead file may be recreated, though this is rare case,
current code will leak the lock, this patch will release lock in
this case.

Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Change-Id: Ifc1fee0fe5a0f377badc3fdf6dc2a6950a26cff6
Reviewed-on: http://review.whamcloud.com/16841
Tested-by: Jenkins
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>