Clarify and add a TODO in the controller
Clarify and add a TODO in the controller

This clarifies and adds a TODO regarding the filters and fields
API parameters.

Change-Id: I01cfd45b99dcfca4e320900caebdc68f6562ddd8

openstack/neutron,eayunstack/neutron,SamYaple/neutron,noironetworks/neutron,dims/neutron,SamYaple/neutron,dhanunjaya/neutron,mahak/neutron,huntxu/neutron,asgard-lab/neutron,eayunstack/neutron,swdream/neutron,asgard-lab/neutron,jumpojoy/neutron,MaximNevrov/neutron,cloudbase/neutron,klmitch/neutron,apporc/neutron,chitr/neutron,sebrandon1/neutron,dhanunjaya/neutron,wolverineav/neutron,yanheven/neutron,jumpojoy/neutron,glove747/liberty-neutron,dims/neutron,apporc/neutron,glove747/liberty-neutron,yanheven/neutron,MaximNevrov/neutron,huntxu/neutron,sebrandon1/neutron,mahak/neutron,openstack/neutron,chitr/neutron,cloudbase/neutron,igor-toga/local-snat,bigswitch/neutron,noironetworks/neutron,klmitch/neutron,bigswitch/neutron,swdream/neutron,JianyuWang/neutron,wolverineav/neutron,JianyuWang/neutron,openstack/neutron,igor-toga/local-snat,mahak/neutron