Support identity API v3 when generate clouds.yaml
Support identity API v3 when generate clouds.yaml

When using IDENTITY_API_VERSION=3, the clouds.yaml must also set
auth/user_domain_id and project_domain_id.

Change-Id: If028f2935ea729276f40039a4003c07c08e91672

vishnugonela/devstack,bq-xiao/devstack,herrsechs/devstack,j4/devstack,bigswitch/devstack,parul24/devstack,samgoon/devstack,costingalan/devstack,HPCHub/devstack,varunarya10/devstack,TwinkleChawla/devstack,atulpatil301/devstack,pczerkas/devstack,j4/devstack,mc2014/devstack,dirkmueller/devstack,pczerkas/devstack,pacinete/devstack,openstack-dev/devstack,ozamiatin/devstack,bswartz/devstack,wenhuizhang/devstack,Mahito/devstack,vsham20/devstack,bq-xiao/devstack,bigswitch/devstack,liuquansheng47/devstack,liuquansheng47/devstack,varunarya10/devstack,mmasaki/devstack,flavio-fernandes/devstack,olivierlemasle/devstack,costingalan/devstack,nawawi/openstack,upadhyay-prashant/devstack,CloudServer/devstack,dirkmueller/devstack,thomasem/devstack,LoHChina/devstack,wenhuizhang/devstack,parul24/devstack,herrsechs/devstack,mmasaki/devstack,HPCHub/devstack,vishnugonela/devstack,samgoon/devstack,atulpatil301/devstack,mssumanth/devstack,richliu/devstack,LoHChina/devstack,NaokiMiyata/devstack,CloudServer/devstack,nawawi/openstack,dtroyer/devstack,TwinkleChawla/devstack,prithivm/branch01,noironetworks/devstack,prithivm/branch01,olivierlemasle/devstack,NaokiMiyata/devstack,pacinete/devstack,group-policy/devstack,group-policy/devstack,pombredanne/devstack,noironetworks/devstack,ozamiatin/devstack,flavio-fernandes/devstack,eharney/devstack,openstack-dev/devstack,thomasem/devstack,upadhyay-prashant/devstack,mssumanth/devstack,pombredanne/devstack,richliu/devstack,vsham20/devstack,bswartz/devstack,avvocatodemarchis/devstack,avvocatodemarchis/devstack,mc2014/devstack,dtroyer/devstack,eharney/devstack,Mahito/devstack