Revert "open_init_pty: Do not make stdin and stdout non-blocking"

Making stdin/stdout non-blocking causes open_init_pty to hang if
they are closed, ala
./open_init_pty bash -c 'echo hello; exec >&- 2>&- <&-; sleep 1; '
and per
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=474956#10

This reverts commit fb081eb64b36a9de5a43f3d69d9e628b6eb1afc7.

Reported-by: Laurent Bigonville <bigon@debian.org>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
1 file changed