[LTP] [PATCH v2] unlink08: use TST_EXP_FAIL(), turn comment into docparse and reword, copyright update

[Petr Vorel]

Hi Avinesh,

I merged with following diff:

* kept relevant headers (It might be a good practise to keep *relevant headers -
library can be rewritten and headers removed, the build would fail).
* fixed docparse formatting (blank line before list is needed

Thanks!

Kind regards,
Petr