MRP-874 deadlock of changelog storing & canceling

Provide correct locking order by starting transaction
before writing to llog

Change-Id: I6e854dee2e20ff500d514715a35fa3387a1060f4
Signed-off-by: Andriy Skulysh <Andriy_Skulysh@xyratex.com>
Reviewed-on: http://morpheus.xyus.xyratex.com:8443/gerrit/271
Reviewed-by: Alexander Zarochentsev <alexander_zarochentsev@xyratex.com>
Tested-by: Jenkins
Reviewed-by: Alexey Lyashkov <Alexey_Lyashkov@xyratex.com>
Tested-by: Alexander Lezhoev <Alexander_Lezhoev@xyratex.com>
Reviewed-by: Vitaly Fertman <Vitaly_Fertman@xyratex.com>