LU-891 test: waiting import state for next step.

LU-891 test: waiting import state for next step.

Anyway, There still has a rare chance that the request meet
a invalid import after recovery. So we should waiting import
restore to a certain state and then doing next operation.

Signed-off-by: yang sheng <ys@whamcloud.com>
Change-Id: I20bed347a16755ccaf102d4c67b0a7e87b1318a1
Reviewed-on: http://review.whamcloud.com/2248
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Johann Lombardi <johann@whamcloud.com>