devstack is not compatible with the current neutron midoNet plugin

[Ryu Ishimoto]

MidoNet plugin has been merged to Havana but devstack has not been upgraded to be compatible with the version merged. This fix includes:

- Remove the need to set up a dedicated virtual router to handle metadata traffic.
- Enable DHCP agent to handle the metadata traffic.
- Change the argument for the script that sets up the MidoNet environment to run Neutron.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/45560

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/45560
Committed: http://github.com/openstack-dev/devstack/commit/35f0966d351c6cf4fe11c7bf482e1d9c02c7dac5
Submitter: Jenkins
Branch: master

commit 35f0966d351c6cf4fe11c7bf482e1d9c02c7dac5
Author: Ryu Ishimoto <email address hidden>
Date: Tue Aug 27 18:32:00 2013 +0900

    Modify midonet plugin to support the latest MidoNet

    MidoNet has been upgraded and devstack needs to be updated to
    be compatible. This change is required to run the current
    version of MidoNet plugin with DevStack.

    Closes-Bug: #1222314
    Change-Id: If3379b4d5da4e4fcf989ee7398b5952d71b68d5a