library: for atexit() support, fix fileutils for EPIPE

library: for atexit() support, fix fileutils for EPIPE

When fileutils with stream error checking was borrowed
from GNU lib, an omission was also propagated where an
errno of EPIPE wouldn't be preserved in close_stream()
making a test for EPIPE in close_stdout() meaningless.

This patch corrects such oversight so that an errno of
EPIPE no longer produces 'write error' at program end.

( gnulib provides for optionally ignoring EPIPE, but )
( if a program chooses to ignore it, then their code )
( appears to suffer from this close_stream oversight )

Reference(s):
. original fileutilis addition
commit c7cf98b0e03780f78abe5275c6fb282f71a2369f
. bugzilla report
https://bugzilla.redhat.com/show_bug.cgi?id=976199