[Quantum] quantum ovs-plugin agent的問題: br-int is not a bridge or a socket

https://github.com/mseknibilel/OpenStack-Folsom-Install-guide/issues/75

https://wiki.openstack.org/wiki/ConfigureOpenvswitch

https://answers.launchpad.net/quantum/+question/181070

https://answers.launchpad.net/quantum/+question/205427