Use F_GETFD/F_SETFD for FD_CLOEXEC.

This mixup may have caused bug #456296 (see commit
e43524dc88774f768441dcb386a534166a53f7fa).
Disable calls to fcntl.fcntl(…, fcntl.F_SETFD, … | fcntl.FD_CLOEXEC) with Python >=3.4,
since FD_CLOEXEC is enabled by default in Python >=3.4.
SpawnProcess: Don't handle FreeBSD fcntl ENOTTY

This error does not occur since the fcntl call was fixed to properly
use the F_GETFD/F_SETFD commands in commit
30c652a9db1014fc720f7d6055520a07b731c984.
_setup_pipes: fix for Python 3.1 to 3.3

This fixes a case where /dev/null stdin fails to inherit since commit
bd2128b7a750a68470f857162784e55b8ac39de2.

Conflicts:
	pym/portage/process.py