make utils.mkfs() more general
make utils.mkfs() more general

While types other than 'vfat' don't seem to be used at present,
it seems better to allow labels on all file system types,
for future maintenance, and to at least alleviate confusion.

Change-Id: I80110eff577e56e9e48354813efbc3e5488d6257

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