Reboot machine if imaging failed

BUG=None
TEST=run crosperf, machine rebooted as expected

Change-Id: I0ffb94d9cc96858d91fb5f8c277c91c8c836b0cf
Reviewed-on: https://gerrit-int.chromium.org/34651
Reviewed-by: Han Shen <shenhan@google.com>
Tested-by: Yunlian Jiang <yunlian@google.com>
Commit-Queue: Yunlian Jiang <yunlian@google.com>
1 file changed