silence warning regarding ignoring pipe's return value
silence warning regarding ignoring pipe's return value

Check's unit tests were calling pipe but ignore its return value.
This results in a compiler warning. The offending unit tests now
check the return value and call ck_assert_msg with it.


git-svn-id: d023f1085a36f7a677188d00334e37d38ffecf51@650 64e312b2-a51f-0410-8e61-82d0ca0eb02a

9fcc/check,brarcher/check,libcheck/check,libcheck/check,brarcher/check,9fcc/check,brarcher/check,krichter722/check,krichter722/check,9fcc/check,krichter722/check,libcheck/check,krichter722/check,9fcc/check,krichter722/check,brarcher/check,9fcc/check,brarcher/check,libcheck/check,libcheck/check