Sometimes O_CLOEXEC is not available.

slapos.zcbworkarounds and slapos.rebootstrap are good in case of Zope related
profiles.

As soon as slapgrid (in slapos.core package) has any package, this package
is passed to used buildout. In this case, beacause of using patched SlapOS
zc.buildout 1.5.3-dev-SlapOS-005, slapos.libnetworkcache will be used.

This reverts commit ee077f3a.

1.5.3-dev-SlapOS-004 does not work correctly with networkcache.

This reverts commit ee077f3a.

This reverts commit ee077f3a.