Non-tested experimental code removal.

There is a new feature that came in with the last sync to the rack stack that should not have
been released. It is untested and may not well work. It currently is off by default, which is good
but it is best to remove it until such time that it can be vetted and tuned to actually work :)

This change removes just the experimental feature for now. It can make a appearance in the future
when it is proofed out.

Reviewed by: tuexen
Differential Revision:https://reviews.freebsd.org/D45410