neutron: ml2+linuxbridge

wip -- needs testing

remove acceptence test
Neutron Open vSwitch to ML2 + LinuxBridge migration playbook
neutron ml2: move firewall driver so neutron-server does security groups
testenv: upgrade to 3.8 kernel for VXLAN support
tests: configure neutron external interface for ML2 CI runs
testenv: add BlueBox OpenStack PPA for iproute2
nova: use Neutron plugin specific interface driver
neutron migration: update nova config and restart nova-compute
neutron ml2: configure linuxbridge-agent to match ML2
vxlan: use IANA assigned port
monitoring: check for the correct neutron agent
vxlan: Install XORP to provide IGMP router
xorp: use IGMP v3
Merge pull request #508 from blueboxgroup/ml2-linuxbridge

Neutron ML2 + linuxbridge