Remove obsolete policy configuration details from docs
Remove obsolete policy configuration details from docs

The policy-enforcement document was written prior to any of the
policy-in-code or policy documentation efforts took place. This
commit updates the developer reference for policy to remove these
details since they have already been implemented.

Subsequent patches will update details of this document by taking into
account the recent keystone and oslo changes that help fix the
original issues described in this document.

Change-Id: I263b2f72037a588623958baccacf78fb6a6be05d

openstack/nova,openstack/nova,rahulunair/nova,rahulunair/nova,klmitch/nova,klmitch/nova,klmitch/nova,klmitch/nova,openstack/nova,mahak/nova,rahulunair/nova,mahak/nova,mahak/nova