qos: kill get_namespace() from service plugin
qos: kill get_namespace() from service plugin

Its usage was removed as of I3c406910991c33cf959c5345d76153eabe3ace2d
that is now included in feature/qos branch.

Change-Id: Iddab10729cf12e3b7425c5d2298f2a6b3436289c

sasukeh/neutron,bigswitch/neutron,adelina-t/neutron,shahbazn/neutron,mattt416/neutron,vivekanand1101/neutron,JianyuWang/neutron,apporc/neutron,mahak/neutron,apporc/neutron,skyddv/neutron,mahak/neutron,sasukeh/neutron,mmnelemane/neutron,javaos74/neutron,glove747/liberty-neutron,cloudbase/neutron,SamYaple/neutron,mmnelemane/neutron,takeshineshiro/neutron,JianyuWang/neutron,neoareslinux/neutron,asgard-lab/neutron,swdream/neutron,klmitch/neutron,jacknjzhou/neutron,MaximNevrov/neutron,igor-toga/local-snat,jacknjzhou/neutron,mattt416/neutron,noironetworks/neutron,shahbazn/neutron,huntxu/neutron,SamYaple/neutron,chitr/neutron,bigswitch/neutron,klmitch/neutron,openstack/neutron,dims/neutron,eayunstack/neutron,vivekanand1101/neutron,mahak/neutron,adelina-t/neutron,dhanunjaya/neutron,wolverineav/neutron,silenci/neutron,openstack/neutron,wolverineav/neutron,javaos74/neutron,sebrandon1/neutron,noironetworks/neutron,jumpojoy/neutron,yanheven/neutron,barnsnake351/neutron,jumpojoy/neutron,asgard-lab/neutron,silenci/neutron,eayunstack/neutron,sebrandon1/neutron,glove747/liberty-neutron,yanheven/neutron,huntxu/neutron,MaximNevrov/neutron,neoareslinux/neutron,takeshineshiro/neutron,igor-toga/local-snat,dims/neutron,chitr/neutron,dhanunjaya/neutron,skyddv/neutron,openstack/neutron,swdream/neutron,cloudbase/neutron,barnsnake351/neutron