fix for pipe() on sparc

fix for pipe() on sparc

When using something like this:
 $ echo foo|grep foo|wc -l
with mksh shell, you get an runtime error.

Glibc and klibc does not do these extra check.
After removing this check using double pipes work fine.
Tested with Qemu 2.1.0.

Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Thorsten Glaser <tg@mirbsd.org>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>