duplicated config-option registering

[Isaku Yamahata]

Some config options(interface_driver, use_namespaces, periodic_interval) are defined in multiple sources in ad-hoc way.
It may cause DuplicateOptError exception when using those module at the same time.
Right now the exception is avoided in ad-hoc way by each executables.
Those definition/registering should be consolidated.

This is the blocker for BP of l3 agent consolidation.
https://blueprints.launchpad.net/neutron/+spec/l3-agent-consolidation

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/73520

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/73520
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=9af846caf7f4d00eddb2d839c032b909eb79d403
Submitter: Jenkins
Branch: master

commit 9af846caf7f4d00eddb2d839c032b909eb79d403
Author: Isaku Yamahata <email address hidden>
Date: Thu Feb 13 20:19:25 2014 +0900

    options: consolidate options definitions

    Some config options(interface_driver, use_namespaces) are defined
    multiple times in ad-hoc way. It causes DuplicateOptError exception
    when using those module at the same time. Right now the exception is
    avoided in ad-hoc way by each executable. Those duplicated
    definitions should be consolidated and treated in uniformed way.

    This is the blocker for blueprint: l3-agent-consolidation

    neutron.services.loadbalancer.drivers.haproxy.agent periodic_interval
    conflicts with neutron.service one. Since there is no way to fix it
    without changing existing behavior/default value, it is untouched for now.

    Closes-bug: #1279769
    Change-Id: Ifed79b7ee0033644854499416f8a2b22a20416fe