[LTP] [PATCH] cpio_tests.sh: Fix failure with BusyBox cpio

[Radoslav Kolev]

Hi Petr, 

On Tue, 2021-01-05 at 12:12 +0100, Petr Vorel wrote:
> Thanks for your fix, merged with these changes:
> 
> * grep for BusyBox because some older versions does not contain the
> hint, but actually require it.
> 
> * move things to setup function due my following commit, which cannot
> be
> outside API functions (setup/test function):
> And check for -o (which is on BusyBox optional).

Thanks a lot for the review and fixes!