This reverts commit d817f62c.

It is not required, as SlapOS node installation profile is responsible for
providing by default good (:= with networkcache) buildout environment.

As older versions of slapos.core will ignore slapos:buildout switch it is safe
to direct them to unexisting one.

New slapos profiles are generating buildout_networkache in self location, so as
already all parameters are hardocded, use such path directly.

Solves "Neighbour table overflow." and network issues.

Still computer key and certificate is there.