Applies neutron-conductor service on OpenStack Havana

<description>

Tested on CentOS 6.4 with ML2 plugin with OVS driver.

== Test Environment ==
https://gist.github.com/zyluo/9522619
Linux devstack-centos64 2.6.32-358.123.2.openstack.el6.x86_64
4 CPU cores
8G memory

== The localrc file used for testing ==
https://gist.github.com/zyluo/9503014

*IMPORTANT*
If you have your own localrc file, be sure you have "enable_service neutron"
added into it. Also note that the conductor service has only been tested
with the ML2 plugin with the OVS driver.

== Stress test script ==
https://gist.github.com/zyluo/9522329

== Verification scipt ==
DHCP_UUID=$(ip netns | grep dhcp | cut -c7-)
IP_CNT=$(cat /opt/stack/data/neutron/dhcp/$DHCP_UUID/host | wc -l)
VM_CNT=$(nova list | grep ACTIVE | awk '{print $12}' | sort | wc -l)
if [[ $IP_CNT -eq $(($VM_CNT+1)) ]]; then echo "OK"; else echo "FAIL"; fi

== Cleanup script ==
nova list | grep ACTIVE | awk '{print $2}' | xargs -l nova delete

== Neutron conductor branch ==
(This branch will be automatically pulled to /opt/stack/neutron)
https://github.com/zyluo/neutron/tree/havana_conductor_sg_only