Refactoring to adhere to coding convention
Refactoring to adhere to coding convention

By convention, internal properties of the DvrRouter class
are initialized to None in the constructor. This patch
initializes the fip_ns property to None in order to adhere
to those guidelines

Change-Id: Ic135102a4c9372fcbbdba261f906b594e247d451

bigswitch/neutron,mattt416/neutron,MaximNevrov/neutron,yanheven/neutron,shahbazn/neutron,cisco-openstack/neutron,bgxavier/neutron,paninetworks/neutron,eonpatapon/neutron,jumpojoy/neutron,yuewko/neutron,noironetworks/neutron,glove747/liberty-neutron,apporc/neutron,mandeepdhami/neutron,JioCloud/neutron,jacknjzhou/neutron,apporc/neutron,klmitch/neutron,cloudbase/neutron,yanheven/neutron,javaos74/neutron,JianyuWang/neutron,takeshineshiro/neutron,shahbazn/neutron,mahak/neutron,skyddv/neutron,infobloxopen/neutron,silenci/neutron,glove747/liberty-neutron,huntxu/neutron,SamYaple/neutron,huntxu/neutron,sebrandon1/neutron,mmnelemane/neutron,SamYaple/neutron,barnsnake351/neutron,wolverineav/neutron,mmnelemane/neutron,cisco-openstack/neutron,igor-toga/local-snat,SmartInfrastructures/neutron,JianyuWang/neutron,SmartInfrastructures/neutron,dhanunjaya/neutron,igor-toga/local-snat,wenhuizhang/neutron,mahak/neutron,eayunstack/neutron,klmitch/neutron,javaos74/neutron,swdream/neutron,paninetworks/neutron,sasukeh/neutron,sasukeh/neutron,suneeth51/neutron,sebrandon1/neutron,neoareslinux/neutron,openstack/neutron,NeCTAR-RC/neutron,adelina-t/neutron,jerryz1982/neutron,antonioUnina/neutron,cloudbase/neutron,openstack/neutron,infobloxopen/neutron,JioCloud/neutron,openstack/neutron,noironetworks/neutron,wolverineav/neutron,barnsnake351/neutron,vivekanand1101/neutron,skyddv/neutron,asgard-lab/neutron,suneeth51/neutron,watonyweng/neutron,chitr/neutron,jerryz1982/neutron,swdream/neutron,chitr/neutron,adelina-t/neutron,bigswitch/neutron,watonyweng/neutron,eonpatapon/neutron,yuewko/neutron,mattt416/neutron,mandeepdhami/neutron,eayunstack/neutron,silenci/neutron,wenhuizhang/neutron,dims/neutron,MaximNevrov/neutron,NeCTAR-RC/neutron,antonioUnina/neutron,dhanunjaya/neutron,bgxavier/neutron,mahak/neutron,vivekanand1101/neutron,neoareslinux/neutron,jacknjzhou/neutron,jumpojoy/neutron,takeshineshiro/neutron,dims/neutron,asgard-lab/neutron