Remove extra_context support in Flags
Remove extra_context support in Flags

This doesn't seem to be used at all any more.

Change-Id: I3a4a1eb271f547ad1723676dc47f1d8c8bad88ea

houshengbo/nova_vmware_compute_driver,sileht/deb-openstack-nova,BeyondTheClouds/nova,eharney/nova,noironetworks/nova,DirectXMan12/nova-hacking,zhimin711/nova,houshengbo/nova_vmware_compute_driver,mandeepdhami/nova,SUSE-Cloud/nova,bgxavier/nova,zaina/nova,vmturbo/nova,Stavitsky/nova,isyippee/nova,berrange/nova,devendermishrajio/nova,aristanetworks/arista-ovs-nova,Yuriy-Leonov/nova,eneabio/nova,JioCloud/nova_test_latest,bclau/nova,gooddata/openstack-nova,redhat-openstack/nova,mmnelemane/nova,vmturbo/nova,watonyweng/nova,cernops/nova,savi-dev/nova,JioCloud/nova_test_latest,openstack/nova,gspilio/nova,klmitch/nova,Tehsmash/nova,Francis-Liu/animated-broccoli,JianyuWang/nova,joker946/nova,leilihh/novaha,sridevikoushik31/openstack,dawnpower/nova,mahak/nova,NoBodyCam/TftpPxeBootBareMetal,maelnor/nova,DirectXMan12/nova-hacking,virtualopensystems/nova,Yuriy-Leonov/nova,MountainWei/nova,zzicewind/nova,jianghuaw/nova,dims/nova,russellb/nova,TwinkleChawla/nova,cyx1231st/nova,gooddata/openstack-nova,Brocade-OpenSource/OpenStack-DNRM-Nova,savi-dev/nova,barnsnake351/nova,Yusuke1987/openstack_template,yatinkumbhare/openstack-nova,cloudbase/nova-virtualbox,gspilio/nova,maheshp/novatest,shootstar/novatest,cernops/nova,raildo/nova,devoid/nova,citrix-openstack-build/nova,usc-isi/nova,gooddata/openstack-nova,blueboxgroup/nova,jeffrey4l/nova,eneabio/nova,whitepages/nova,rickerc/nova_audit,eayunstack/nova,j-carpentier/nova,sileht/deb-openstack-nova,aristanetworks/arista-ovs-nova,paulmathews/nova,vladikr/nova_drafts,shahar-stratoscale/nova,yosshy/nova,affo/nova,redhat-openstack/nova,fnordahl/nova,alexandrucoman/vbox-nova-driver,rickerc/nova_audit,felixma/nova,Triv90/Nova,phenoxim/nova,varunarya10/nova_test_latest,Triv90/Nova,takeshineshiro/nova,noironetworks/nova,mandeepdhami/nova,citrix-openstack-build/nova,tudorvio/nova,sebrandon1/nova,jianghuaw/nova,JioCloud/nova,Yusuke1987/openstack_template,sebrandon1/nova,vladikr/nova_drafts,dstroppa/openstack-smartos-nova-grizzly,maheshp/novatest,ruslanloman/nova,CEG-FYP-OpenStack/scheduler,orbitfp7/nova,eayunstack/nova,sridevikoushik31/openstack,devendermishrajio/nova_test_latest,viggates/nova,Metaswitch/calico-nova,sacharya/nova,badock/nova,usc-isi/nova,usc-isi/extra-specs,akash1808/nova,CloudServer/nova,devendermishrajio/nova_test_latest,tianweizhang/nova,alexandrucoman/vbox-nova-driver,petrutlucian94/nova_dev,alaski/nova,dstroppa/openstack-smartos-nova-grizzly,CloudServer/nova,felixma/nova,TieWei/nova,maelnor/nova,zhimin711/nova,silenceli/nova,tianweizhang/nova,projectcalico/calico-nova,double12gzh/nova,BeyondTheClouds/nova,rahulunair/nova,hanlind/nova,zzicewind/nova,iuliat/nova,devoid/nova,ewindisch/nova,Juniper/nova,saleemjaveds/https-github.com-openstack-nova,rrader/nova-docker-plugin,fajoy/nova,alaski/nova,NeCTAR-RC/nova,maoy/zknova,silenceli/nova,mahak/nova,sridevikoushik31/nova,cloudbau/nova,cloudbase/nova,luogangyi/bcec-nova,leilihh/nova,petrutlucian94/nova_dev,JianyuWang/nova,yrobla/nova,NeCTAR-RC/nova,ruslanloman/nova,Metaswitch/calico-nova,russellb/nova,raildo/nova,Juniper/nova,openstack/nova,sacharya/nova,sridevikoushik31/nova,scripnichenko/nova,mgagne/nova,kimjaejoong/nova,belmiromoreira/nova,shail2810/nova,klmitch/nova,devendermishrajio/nova,klmitch/nova,thomasem/nova,apporc/nova,maoy/zknova,tanglei528/nova,houshengbo/nova_vmware_compute_driver,OpenAcademy-OpenStack/nova-scheduler,yatinkumbhare/openstack-nova,rrader/nova-docker-plugin,Tehsmash/nova,projectcalico/calico-nova,klmitch/nova,isyippee/nova,NewpTone/stacklab-nova,qwefi/nova,bclau/nova,rahulunair/nova,cloudbau/nova,watonyweng/nova,akash1808/nova_test_latest,rajalokan/nova,sridevikoushik31/nova,NewpTone/stacklab-nova,vmturbo/nova,tangfeixiong/nova,NoBodyCam/TftpPxeBootBareMetal,shootstar/novatest,spring-week-topos/nova-week,cloudbase/nova,vmturbo/nova,bigswitch/nova,rajalokan/nova,maheshp/novatest,alvarolopez/nova,whitepages/nova,ntt-sic/nova,aristanetworks/arista-ovs-nova,barnsnake351/nova,rajalokan/nova,akash1808/nova_test_latest,NewpTone/stacklab-nova,spring-week-topos/nova-week,KarimAllah/nova,SUSE-Cloud/nova,rajalokan/nova,tealover/nova,paulmathews/nova,mahak/nova,angdraug/nova,zaina/nova,MountainWei/nova,eonpatapon/nova,mmnelemane/nova,apporc/nova,yrobla/nova,DirectXMan12/nova-hacking,ted-gould/nova,imsplitbit/nova,CiscoSystems/nova,mikalstill/nova,cloudbase/nova-virtualbox,iuliat/nova,TieWei/nova,sridevikoushik31/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,dawnpower/nova,adelina-t/nova,NoBodyCam/TftpPxeBootBareMetal,affo/nova,ted-gould/nova,hanlind/nova,joker946/nova,bigswitch/nova,usc-isi/extra-specs,LoHChina/nova,badock/nova,gooddata/openstack-nova,fnordahl/nova,shahar-stratoscale/nova,Juniper/nova,psiwczak/openstack,tudorvio/nova,Triv90/Nova,TwinkleChawla/nova,dims/nova,j-carpentier/nova,phenoxim/nova,KarimAllah/nova,luogangyi/bcec-nova,CCI-MOC/nova,adelina-t/nova,CEG-FYP-OpenStack/scheduler,plumgrid/plumgrid-nova,LoHChina/nova,belmiromoreira/nova,blueboxgroup/nova,double12gzh/nova,fajoy/nova,josephsuh/extra-specs,usc-isi/nova,fajoy/nova,petrutlucian94/nova,angdraug/nova,tealover/nova,jianghuaw/nova,orbitfp7/nova,openstack/nova,kimjaejoong/nova,edulramirez/nova,CCI-MOC/nova,hanlind/nova,josephsuh/extra-specs,Francis-Liu/animated-broccoli,usc-isi/extra-specs,nikesh-mahalka/nova,leilihh/nova,edulramirez/nova,thomasem/nova,tangfeixiong/nova,mikalstill/nova,josephsuh/extra-specs,dstroppa/openstack-smartos-nova-grizzly,cernops/nova,maoy/zknova,berrange/nova,eonpatapon/nova,ntt-sic/nova,JioCloud/nova,psiwczak/openstack,takeshineshiro/nova,plumgrid/plumgrid-nova,sebrandon1/nova,imsplitbit/nova,saleemjaveds/https-github.com-openstack-nova,petrutlucian94/nova,savi-dev/nova,paulmathews/nova,mgagne/nova,alvarolopez/nova,scripnichenko/nova,BeyondTheClouds/nova,psiwczak/openstack,qwefi/nova,eharney/nova,gspilio/nova,KarimAllah/nova,sileht/deb-openstack-nova,viggates/nova,jeffrey4l/nova,Juniper/nova,cyx1231st/nova,bgxavier/nova,leilihh/novaha,mikalstill/nova,nikesh-mahalka/nova,virtualopensystems/nova,CiscoSystems/nova,cloudbase/nova,varunarya10/nova_test_latest,tanglei528/nova,jianghuaw/nova,sridevikoushik31/openstack,OpenAcademy-OpenStack/nova-scheduler,shail2810/nova,akash1808/nova,Stavitsky/nova,yosshy/nova,eneabio/nova,yrobla/nova,russellb/nova,ewindisch/nova,rahulunair/nova