Deletion of DHCP should be notified to the security group rpc

[Nachi Ueno]

Deletion of DHCP should be notified to the security group rpc.

Note: This common logic should be in security_group_rpc_base

[Akihiro Motoki (amotoki)]

This is based on the comment https://review.openstack.org/#/c/19436/14/quantum/plugins/openvswitch/ovs_quantum_plugin.py

-----
We need to inform dhcp ip address when a port for dhcp server is deleted. enable_dhcp in subnet may be changed by update_subnet. The same thing can say to linux bridge plugin.

The logic like this is important, so it should be implemented as a common logic even if the logic is very short. security_group_rpc_base is a good place.

Don't we need to take care the same thing for update_port? IMO, we do not need to take care of it since update device_owner is set by programs (nova vif plugiing, dhcp-agent or so on).
-----

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/23240

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/23240
Committed: http://github.com/openstack/quantum/commit/705dde46dd17caa03617b17609b6e935dc875948
Submitter: Jenkins
Branch: master

commit 705dde46dd17caa03617b17609b6e935dc875948
Author: Nachi Ueno <email address hidden>
Date: Thu Feb 28 16:46:52 2013 -0800

    Notify creation or deletion of dhcp port for security group

    fixes bug 1103840

    Change-Id: I8031bc607a874871a8081575bce1526b3453aff6