The go std os package to will always make sure to use O_CLOEXEC, however
in cases where we directly call unix.Open() we need to pass that flag
explicitly.
I looked at this as there was a report of a leaked fd on the pasta list,
though I am not sure this will address it.
But anyway doing this should be rather safe and avoid leaks into other
processes.
Signed-off-by: Paul Holzinger <pholzing@redhat.com>