Sets policy settings so V3 API extensions are discoverable
Sets policy settings so V3 API extensions are discoverable

Adds the policy settings so the V3 API extensions
are by default discoverable through /v3/extensions. Some of
these policy settings were missed during the porting of
the extensions as the ability to make extensions not discoverable
was done part way through.

Partially implements blueprint nova-v3-api

Change-Id: If2efa15a437d97be8bc026fb04c46ec47eef056f

CCI-MOC/nova,tianweizhang/nova,citrix-openstack-build/nova,shail2810/nova,jianghuaw/nova,alaski/nova,tanglei528/nova,projectcalico/calico-nova,angdraug/nova,JioCloud/nova_test_latest,openstack/nova,tudorvio/nova,bclau/nova,devendermishrajio/nova,yosshy/nova,Yusuke1987/openstack_template,thomasem/nova,varunarya10/nova_test_latest,JioCloud/nova_test_latest,gooddata/openstack-nova,LoHChina/nova,joker946/nova,nikesh-mahalka/nova,ntt-sic/nova,alexandrucoman/vbox-nova-driver,jianghuaw/nova,bigswitch/nova,yatinkumbhare/openstack-nova,tanglei528/nova,hanlind/nova,double12gzh/nova,sebrandon1/nova,ewindisch/nova,alaski/nova,rahulunair/nova,eayunstack/nova,petrutlucian94/nova,devoid/nova,zaina/nova,mandeepdhami/nova,Tehsmash/nova,zaina/nova,Juniper/nova,cernops/nova,openstack/nova,mikalstill/nova,raildo/nova,cloudbase/nova,silenceli/nova,badock/nova,akash1808/nova_test_latest,rrader/nova-docker-plugin,shahar-stratoscale/nova,petrutlucian94/nova,rajalokan/nova,watonyweng/nova,virtualopensystems/nova,blueboxgroup/nova,klmitch/nova,belmiromoreira/nova,MountainWei/nova,shail2810/nova,j-carpentier/nova,vmturbo/nova,edulramirez/nova,devendermishrajio/nova_test_latest,MountainWei/nova,Juniper/nova,mgagne/nova,cyx1231st/nova,vladikr/nova_drafts,cloudbase/nova,thomasem/nova,eonpatapon/nova,dims/nova,akash1808/nova,takeshineshiro/nova,Tehsmash/nova,mahak/nova,jeffrey4l/nova,mmnelemane/nova,Metaswitch/calico-nova,mahak/nova,ntt-sic/nova,rickerc/nova_audit,saleemjaveds/https-github.com-openstack-nova,leilihh/novaha,BeyondTheClouds/nova,yatinkumbhare/openstack-nova,double12gzh/nova,mmnelemane/nova,imsplitbit/nova,Francis-Liu/animated-broccoli,iuliat/nova,cloudbase/nova-virtualbox,imsplitbit/nova,mikalstill/nova,rrader/nova-docker-plugin,felixma/nova,akash1808/nova,rahulunair/nova,cloudbau/nova,bgxavier/nova,Stavitsky/nova,CloudServer/nova,maelnor/nova,citrix-openstack-build/nova,redhat-openstack/nova,NeCTAR-RC/nova,alexandrucoman/vbox-nova-driver,virtualopensystems/nova,leilihh/novaha,JianyuWang/nova,nikesh-mahalka/nova,gooddata/openstack-nova,belmiromoreira/nova,JianyuWang/nova,Francis-Liu/animated-broccoli,Metaswitch/calico-nova,silenceli/nova,felixma/nova,tangfeixiong/nova,mikalstill/nova,CiscoSystems/nova,mandeepdhami/nova,varunarya10/nova_test_latest,spring-week-topos/nova-week,rajalokan/nova,OpenAcademy-OpenStack/nova-scheduler,whitepages/nova,eharney/nova,adelina-t/nova,leilihh/nova,ted-gould/nova,tealover/nova,raildo/nova,sebrandon1/nova,TwinkleChawla/nova,luogangyi/bcec-nova,bclau/nova,ruslanloman/nova,takeshineshiro/nova,tudorvio/nova,viggates/nova,TieWei/nova,berrange/nova,maelnor/nova,saleemjaveds/https-github.com-openstack-nova,zhimin711/nova,ruslanloman/nova,jianghuaw/nova,bigswitch/nova,cloudbau/nova,spring-week-topos/nova-week,CEG-FYP-OpenStack/scheduler,rahulunair/nova,yosshy/nova,edulramirez/nova,cloudbase/nova,luogangyi/bcec-nova,klmitch/nova,rajalokan/nova,dims/nova,Yuriy-Leonov/nova,tangfeixiong/nova,gooddata/openstack-nova,joker946/nova,mahak/nova,apporc/nova,klmitch/nova,CEG-FYP-OpenStack/scheduler,kimjaejoong/nova,eonpatapon/nova,SUSE-Cloud/nova,BeyondTheClouds/nova,petrutlucian94/nova_dev,Yusuke1987/openstack_template,alvarolopez/nova,isyippee/nova,devendermishrajio/nova,rajalokan/nova,angdraug/nova,hanlind/nova,jianghuaw/nova,rickerc/nova_audit,affo/nova,leilihh/nova,zzicewind/nova,SUSE-Cloud/nova,vladikr/nova_drafts,orbitfp7/nova,phenoxim/nova,vmturbo/nova,affo/nova,ewindisch/nova,bgxavier/nova,TwinkleChawla/nova,blueboxgroup/nova,dawnpower/nova,JioCloud/nova,berrange/nova,zhimin711/nova,whitepages/nova,eharney/nova,Juniper/nova,cernops/nova,devendermishrajio/nova_test_latest,eayunstack/nova,LoHChina/nova,cloudbase/nova-virtualbox,badock/nova,Stavitsky/nova,fnordahl/nova,kimjaejoong/nova,CiscoSystems/nova,cyx1231st/nova,j-carpentier/nova,openstack/nova,dawnpower/nova,adelina-t/nova,Yuriy-Leonov/nova,BeyondTheClouds/nova,viggates/nova,hanlind/nova,tealover/nova,devoid/nova,petrutlucian94/nova_dev,Juniper/nova,watonyweng/nova,gooddata/openstack-nova,mgagne/nova,scripnichenko/nova,vmturbo/nova,isyippee/nova,iuliat/nova,sacharya/nova,tianweizhang/nova,NeCTAR-RC/nova,projectcalico/calico-nova,jeffrey4l/nova,sebrandon1/nova,apporc/nova,alvarolopez/nova,fnordahl/nova,cernops/nova,barnsnake351/nova,shahar-stratoscale/nova,CCI-MOC/nova,orbitfp7/nova,JioCloud/nova,phenoxim/nova,OpenAcademy-OpenStack/nova-scheduler,akash1808/nova_test_latest,zzicewind/nova,vmturbo/nova,TieWei/nova,barnsnake351/nova,redhat-openstack/nova,scripnichenko/nova,noironetworks/nova,klmitch/nova,noironetworks/nova,ted-gould/nova,sacharya/nova,CloudServer/nova