Small code cleanup for config_disk handling.
Small code cleanup for config_disk handling.

Change-Id: I3456b4c98aa6527d10452e8f578a30e95a65db8e

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