Don't set the dns managers
Don't set the dns managers

Revert to previous behavior, pick up whatever is set as default
in nova. This was causing an issue in a tempest run. Tempest has
a test where multiple servers can be spun up with the same name
this test failed.

Change-Id: Ie71eda94caf38db0489d6b2385dc80808a39864d

liuquansheng47/devstack,mc2014/devstack,avvocatodemarchis/devstack,dirkmueller/devstack,openstack-dev/devstack,mmasaki/devstack,group-policy/devstack,noironetworks/devstack,ewindisch/raspi-devstack,liuquansheng47/devstack,Mahito/devstack,costingalan/devstack,eharney/devstack,NaokiMiyata/devstack,srics/devstack,costingalan/devstack,mmasaki/devstack,cloudbuilders/devstack,richliu/devstack,mssumanth/devstack,ozamiatin/devstack,tianweizhang/devstack,bigswitch/devstack,NaokiMiyata/devstack,atulpatil301/devstack,nuxeh/devstack,LoHChina/devstack,CloudServer/devstack,eshnil2000/devstack,bljgaurav/openstack-test,deepakselvaraj/devstack,innodee/openstackk,dtroyer/devstack,pacinete/devstack,HPCHub/devstack,Yuriy-Leonov/devstack,promptworks/devstack,vsham20/devstack,williamthegrey/devstack,andrewrothstein/devstack,JioCloud/devstack,ewindisch/raspi-devstack,wenhuizhang/devstack,flavio-fernandes/devstack,bljgaurav/openstack-test,kplus/devstack-moonshot,jamielennox/devstack,Mahito/devstack,BSJAIN92/OpenStack,eharney/devstack,affo/devstack,sc68cal/devstack,dtroyer/devstack,samgoon/devstack,pombredanne/devstack,Millnert/contrail-devstack,shootstar/devstacktest,sc68cal/devstack,CiscoSystems/devstack,vsham20/devstack,ozamiatin/devstack,pombredanne/devstack,pacinete/devstack,CloudServer/devstack,andrewrothstein/devstack,sequenceiq/devstack,thomasem/devstack,prithivm/branch01,olivierlemasle/devstack,LoHChina/devstack,parul24/devstack,bigswitch/devstack,affo/devstack,vishnugonela/devstack,rushiagr/devstack,nawawi/openstack,varunarya10/devstack,j4/devstack,samgoon/devstack,flavio-fernandes/devstack,yamt/devstack,herrsechs/devstack,mc2014/devstack,vishnugonela/devstack,promptworks/devstack,thomasem/devstack,varunarya10/devstack,openstack-dev/devstack,dirkmueller/devstack,virtualopensystems/devstack,j4/devstack,bswartz/devstack,TwinkleChawla/devstack,cloudbuilders/devstack,inkerra/devstack,armando-migliaccio/devstack,rushiagr/devstack,avvocatodemarchis/devstack,nuxeh/devstack,pczerkas/devstack,HPCHub/devstack,neerja28/Devstack_GlusterFS,neerja28/Devstack_GlusterFS,sstrato/devstack,bq-xiao/devstack,herrsechs/devstack,upadhyay-prashant/devstack,richliu/devstack,atulpatil301/devstack,pczerkas/devstack,tianweizhang/devstack,kplus/devstack-moonshot,Juniper/devstack,bswartz/devstack,bq-xiao/devstack,parul24/devstack,sequenceiq/devstack,upadhyay-prashant/devstack,TwinkleChawla/devstack,olivierlemasle/devstack,BSJAIN92/OpenStack,nawawi/openstack,mssumanth/devstack,wenhuizhang/devstack,prithivm/branch01,group-policy/devstack,noironetworks/devstack