Refactor instance image property inheritance out to a method.
Refactor instance image property inheritance out to a method.

Change-Id: I14c3ff3981b610893296b59ea6a09a9f21b19133

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