Register an extend_dict function for ext_gw_mode extension
Register an extend_dict function for ext_gw_mode extension

Bug 1223585wq

Use dict extension methods instead of overriding make_router_dict in
order to make this extension consistent with all the others.

Change-Id: I94fa7e70e5a869963ec4dfa9de85c8d922976843

leeseulstack/openstack,miyakz1192/neutron,jumpojoy/neutron,netscaler/neutron,yamahata/neutron,Metaswitch/calico-neutron,silenci/neutron,sebrandon1/neutron,Comcast/neutron,Juniper/neutron,antonioUnina/neutron,cloudbase/neutron,vijayendrabvs/ssl-neutron,leeseuljeong/leeseulstack_neutron,pnavarro/neutron,noironetworks/neutron,netscaler/neutron,projectcalico/calico-neutron,takeshineshiro/neutron,cisco-openstack/neutron,zhhf/charging,dhanunjaya/neutron,cernops/neutron,yamahata/neutron,rickerc/neutron_audit,CiscoSystems/vespa,NeCTAR-RC/neutron,suneeth51/neutron,MaximNevrov/neutron,sasukeh/neutron,MaximNevrov/neutron,oeeagle/quantum,netscaler/neutron,watonyweng/neutron,gkotton/neutron,vijayendrabvs/hap,Metaswitch/calico-neutron,kaiweifan/neutron,bigswitch/neutron,mmnelemane/neutron,yuewko/neutron,virtualopensystems/neutron,eonpatapon/neutron,jacknjzhou/neutron,wenhuizhang/neutron,leeseuljeong/leeseulstack_neutron,yamahata/tacker,yanheven/neutron,Stavitsky/neutron,mattt416/neutron,redhat-openstack/neutron,leeseuljeong/leeseulstack_neutron,asgard-lab/neutron,JioCloud/neutron,skyddv/neutron,Comcast/neutron,antonioUnina/neutron,vijayendrabvs/ssl-neutron,magic0704/neutron,klmitch/neutron,vijayendrabvs/hap,ntt-sic/neutron,alexandrucoman/vbox-neutron-agent,leeseulstack/openstack,yamahata/tacker,rickerc/neutron_audit,sajuptpm/neutron-ipam,yuewko/neutron,leeseulstack/openstack,blueboxgroup/neutron,CiscoSystems/vespa,mahak/neutron,vbannai/neutron,glove747/liberty-neutron,openstack/neutron,magic0704/neutron,waltBB/neutron_read,vveerava/Openstack,adelina-t/neutron,cloudbase/neutron-virtualbox,beagles/neutron_hacking,sajuptpm/neutron-ipam,chitr/neutron,paninetworks/neutron,alexandrucoman/vbox-neutron-agent,oeeagle/quantum,igor-toga/local-snat,SmartInfrastructures/neutron,kaiweifan/neutron,CiscoSystems/neutron,wenhuizhang/neutron,infobloxopen/neutron,mandeepdhami/neutron,Juniper/neutron,watonyweng/neutron,rdo-management/neutron,beagles/neutron_hacking,CiscoSystems/vespa,yamahata/neutron,CiscoSystems/neutron,barnsnake351/neutron,vijayendrabvs/hap,sajuptpm/neutron-ipam,miyakz1192/neutron,dims/neutron,adelina-t/neutron,gopal1cloud/neutron,apporc/neutron,mandeepdhami/neutron,JianyuWang/neutron,Juniper/neutron,vbannai/neutron,dhanunjaya/neutron,cloudbase/neutron-virtualbox,NeCTAR-RC/neutron,vivekanand1101/neutron,blueboxgroup/neutron,SmartInfrastructures/neutron,gopal1cloud/neutron,zhhf/charging,virtualopensystems/neutron,Juniper/contrail-dev-neutron,vbannai/neutron,JianyuWang/neutron,swdream/neutron,bgxavier/neutron,swdream/neutron,vivekanand1101/neutron,SamYaple/neutron,jerryz1982/neutron,vveerava/Openstack,wolverineav/neutron,gkotton/neutron,openstack/neutron,huntxu/neutron,huntxu/neutron,cernops/neutron,openstack/neutron,mmnelemane/neutron,chitr/neutron,mahak/neutron,asgard-lab/neutron,ntt-sic/neutron,Comcast/neutron,javaos74/neutron,skyddv/neutron,eayunstack/neutron,citrix-openstack-build/neutron,blueboxgroup/neutron,Juniper/contrail-dev-neutron,vveerava/Openstack,virtualopensystems/neutron,projectcalico/calico-neutron,dims/neutron,rickerc/neutron_audit,bgxavier/neutron,klmitch/neutron,Stavitsky/neutron,cisco-openstack/neutron,bigswitch/neutron,javaos74/neutron,cloudbase/neutron,mahak/neutron,wolverineav/neutron,sasukeh/neutron,SamYaple/neutron,shahbazn/neutron,waltBB/neutron_read,noironetworks/neutron,neoareslinux/neutron,citrix-openstack-build/neutron,eonpatapon/neutron,pnavarro/neutron,ntt-sic/neutron,zhhf/charging,eayunstack/neutron,silenci/neutron,aristanetworks/neutron,takeshineshiro/neutron,CiscoSystems/neutron,glove747/liberty-neutron,yanheven/neutron,mattt416/neutron,gkotton/neutron,citrix-openstack-build/neutron,suneeth51/neutron,Juniper/contrail-dev-neutron,barnsnake351/neutron,rdo-management/neutron,beagles/neutron_hacking,yamahata/tacker,neoareslinux/neutron,infobloxopen/neutron,redhat-openstack/neutron,paninetworks/neutron,vijayendrabvs/ssl-neutron,igor-toga/local-snat,aristanetworks/neutron,JioCloud/neutron,apporc/neutron,shahbazn/neutron,kaiweifan/neutron,sebrandon1/neutron,jumpojoy/neutron,jerryz1982/neutron,jacknjzhou/neutron