Update README to reflect ML2 Exception in Dir Tree
Update README to reflect ML2 Exception in Dir Tree

Will place all ML2 related plugins into its own directory.
Updated README to reflect the exception for ML2.

Change-Id: Ibf5a827e70ac6c6079f68f3a93fcd3de21bd7934

eayunstack/neutron,mahak/neutron,noironetworks/neutron,openstack/neutron,cloudbase/neutron,mahak/neutron,sebrandon1/neutron,igor-toga/local-snat,openstack/neutron,noironetworks/neutron,sebrandon1/neutron,igor-toga/local-snat,huntxu/neutron,eayunstack/neutron,huntxu/neutron,mahak/neutron,cloudbase/neutron,openstack/neutron