[LTP] [PATCH] pipe13: Increase time to wait for child processes to terminate

[Yang Xu]

Hi Joerg
> From: Joerg Vehlow<joerg.vehlow@aox-tech.de>
>
> If the system is not fast enough, to clean up
> the child processes, the test shows a false negative result.
Pushed, thanks.

Best Regards
Yang Xu