[TrivialFix] Deprecate unused NeutronController class
[TrivialFix] Deprecate unused NeutronController class

Change-Id: I2bb527c7833a50642ff517adb926f5d274e3d302

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