Add OpenStack API support for block_device_mapping.
Add OpenStack API support for block_device_mapping.

This patch enables boot from volume feature already implemented in EC2
API, as an OpenStack API extension.
maheshp/novatest,Triv90/Nova,eneabio/nova,NoBodyCam/TftpPxeBootBareMetal,rickerc/nova_audit,fnordahl/nova,LoHChina/nova,qwefi/nova,raildo/nova,maoy/zknova,DirectXMan12/nova-hacking,sridevikoushik31/nova,Yuriy-Leonov/nova,apporc/nova,shahar-stratoscale/nova,adelina-t/nova,yosshy/nova,mikalstill/nova,NewpTone/stacklab-nova,cloudbase/nova,berrange/nova,jianghuaw/nova,nikesh-mahalka/nova,bgxavier/nova,double12gzh/nova,bigswitch/nova,Brocade-OpenSource/OpenStack-DNRM-Nova,rahulunair/nova,plumgrid/plumgrid-nova,zhimin711/nova,KarimAllah/nova,JianyuWang/nova,BeyondTheClouds/nova,Juniper/nova,spring-week-topos/nova-week,joker946/nova,shail2810/nova,alvarolopez/nova,DirectXMan12/nova-hacking,mikalstill/nova,sridevikoushik31/nova,psiwczak/openstack,double12gzh/nova,CiscoSystems/nova,rahulunair/nova,akash1808/nova_test_latest,maelnor/nova,devendermishrajio/nova_test_latest,zaina/nova,redhat-openstack/nova,edulramirez/nova,NewpTone/stacklab-nova,Metaswitch/calico-nova,salv-orlando/MyRepo,paulmathews/nova,projectcalico/calico-nova,hanlind/nova,tianweizhang/nova,Triv90/Nova,sacharya/nova,leilihh/novaha,isyippee/nova,scripnichenko/nova,klmitch/nova,sacharya/nova,leilihh/nova,varunarya10/nova_test_latest,iuliat/nova,gspilio/nova,DirectXMan12/nova-hacking,Brocade-OpenSource/OpenStack-DNRM-Nova,shail2810/nova,takeshineshiro/nova,psiwczak/openstack,Yuriy-Leonov/nova,jianghuaw/nova,mandeepdhami/nova,CCI-MOC/nova,sridevikoushik31/openstack,whitepages/nova,tanglei528/nova,usc-isi/nova,belmiromoreira/nova,paulmathews/nova,jeffrey4l/nova,mahak/nova,tealover/nova,angdraug/nova,Juniper/nova,CEG-FYP-OpenStack/scheduler,badock/nova,redhat-openstack/nova,alvarolopez/nova,OpenAcademy-OpenStack/nova-scheduler,ruslanloman/nova,TieWei/nova,usc-isi/nova,josephsuh/extra-specs,usc-isi/extra-specs,NoBodyCam/TftpPxeBootBareMetal,fajoy/nova,felixma/nova,devoid/nova,maoy/zknova,eayunstack/nova,sebrandon1/nova,openstack/nova,gooddata/openstack-nova,bclau/nova,silenceli/nova,tangfeixiong/nova,belmiromoreira/nova,whitepages/nova,sileht/deb-openstack-nova,virtualopensystems/nova,aristanetworks/arista-ovs-nova,virtualopensystems/nova,Triv90/Nova,zzicewind/nova,russellb/nova,tangfeixiong/nova,apporc/nova,sridevikoushik31/openstack,ewindisch/nova,ted-gould/nova,Tehsmash/nova,hanlind/nova,gspilio/nova,qwefi/nova,cloudbase/nova-virtualbox,jianghuaw/nova,cernops/nova,JioCloud/nova_test_latest,mandeepdhami/nova,eneabio/nova,thomasem/nova,CloudServer/nova,sebrandon1/nova,rrader/nova-docker-plugin,yosshy/nova,sileht/deb-openstack-nova,ntt-sic/nova,Stavitsky/nova,eharney/nova,alexandrucoman/vbox-nova-driver,viggates/nova,gooddata/openstack-nova,rahulunair/nova,openstack/nova,phenoxim/nova,joker946/nova,maoy/zknova,petrutlucian94/nova_dev,vmturbo/nova,gspilio/nova,maelnor/nova,usc-isi/extra-specs,mgagne/nova,badock/nova,MountainWei/nova,barnsnake351/nova,akash1808/nova,leilihh/novaha,Yusuke1987/openstack_template,Yusuke1987/openstack_template,mmnelemane/nova,sridevikoushik31/nova,cloudbau/nova,phenoxim/nova,tudorvio/nova,citrix-openstack-build/nova,jeffrey4l/nova,rajalokan/nova,dstroppa/openstack-smartos-nova-grizzly,raildo/nova,leilihh/nova,viggates/nova,gooddata/openstack-nova,mmnelemane/nova,devendermishrajio/nova,rrader/nova-docker-plugin,rajalokan/nova,mikalstill/nova,CCI-MOC/nova,devendermishrajio/nova_test_latest,shootstar/novatest,cernops/nova,dims/nova,j-carpentier/nova,vladikr/nova_drafts,affo/nova,tudorvio/nova,petrutlucian94/nova,devendermishrajio/nova,rajalokan/nova,tianweizhang/nova,zhimin711/nova,blueboxgroup/nova,klmitch/nova,akash1808/nova,eayunstack/nova,cloudbase/nova-virtualbox,alexandrucoman/vbox-nova-driver,JianyuWang/nova,vmturbo/nova,bigswitch/nova,edulramirez/nova,alaski/nova,orbitfp7/nova,KarimAllah/nova,klmitch/nova,SUSE-Cloud/nova,plumgrid/plumgrid-nova,salv-orlando/MyRepo,josephsuh/extra-specs,nikesh-mahalka/nova,rickerc/nova_audit,watonyweng/nova,shahar-stratoscale/nova,imsplitbit/nova,adelina-t/nova,tanglei528/nova,felixma/nova,orbitfp7/nova,vladikr/nova_drafts,savi-dev/nova,TieWei/nova,KarimAllah/nova,cloudbase/nova,houshengbo/nova_vmware_compute_driver,j-carpentier/nova,cyx1231st/nova,yrobla/nova,Tehsmash/nova,gooddata/openstack-nova,jianghuaw/nova,mgagne/nova,saleemjaveds/https-github.com-openstack-nova,psiwczak/openstack,sileht/deb-openstack-nova,citrix-openstack-build/nova,vmturbo/nova,luogangyi/bcec-nova,shootstar/novatest,TwinkleChawla/nova,JioCloud/nova,ted-gould/nova,Metaswitch/calico-nova,SUSE-Cloud/nova,cernops/nova,eonpatapon/nova,CEG-FYP-OpenStack/scheduler,maheshp/novatest,dstroppa/openstack-smartos-nova-grizzly,kimjaejoong/nova,MountainWei/nova,Stavitsky/nova,spring-week-topos/nova-week,sebrandon1/nova,silenceli/nova,aristanetworks/arista-ovs-nova,imsplitbit/nova,ruslanloman/nova,noironetworks/nova,zzicewind/nova,rajalokan/nova,eneabio/nova,houshengbo/nova_vmware_compute_driver,isyippee/nova,saleemjaveds/https-github.com-openstack-nova,CloudServer/nova,fajoy/nova,Francis-Liu/animated-broccoli,BeyondTheClouds/nova,luogangyi/bcec-nova,bgxavier/nova,fajoy/nova,watonyweng/nova,fnordahl/nova,scripnichenko/nova,yatinkumbhare/openstack-nova,eharney/nova,NeCTAR-RC/nova,salv-orlando/MyRepo,mahak/nova,zaina/nova,JioCloud/nova_test_latest,klmitch/nova,yrobla/nova,kimjaejoong/nova,Francis-Liu/animated-broccoli,NeCTAR-RC/nova,yrobla/nova,russellb/nova,hanlind/nova,iuliat/nova,noironetworks/nova,NoBodyCam/TftpPxeBootBareMetal,barnsnake351/nova,paulmathews/nova,sridevikoushik31/nova,Juniper/nova,affo/nova,cloudbase/nova,blueboxgroup/nova,josephsuh/extra-specs,petrutlucian94/nova,houshengbo/nova_vmware_compute_driver,devoid/nova,russellb/nova,OpenAcademy-OpenStack/nova-scheduler,thomasem/nova,JioCloud/nova,usc-isi/extra-specs,cyx1231st/nova,savi-dev/nova,yatinkumbhare/openstack-nova,petrutlucian94/nova_dev,eonpatapon/nova,BeyondTheClouds/nova,angdraug/nova,dawnpower/nova,sridevikoushik31/openstack,savi-dev/nova,dawnpower/nova,varunarya10/nova_test_latest,aristanetworks/arista-ovs-nova,CiscoSystems/nova,tealover/nova,dims/nova,ewindisch/nova,usc-isi/nova,openstack/nova,NewpTone/stacklab-nova,akash1808/nova_test_latest,projectcalico/calico-nova,alaski/nova,TwinkleChawla/nova,vmturbo/nova,Juniper/nova,takeshineshiro/nova,ntt-sic/nova,berrange/nova,cloudbau/nova,LoHChina/nova,maheshp/novatest,dstroppa/openstack-smartos-nova-grizzly,bclau/nova,mahak/nova