Enable the correct instance managers for instance/floating ips.
Enable the correct instance managers for instance/floating ips.

Currently the default is nova.network.dns_driver.DNSDriver for
both. We need to switch to nova.network.minidns.MiniDNS for
both instance_dns_manager and floating_ip_dns_manager.
nova.network.dns_driver.DNSDriver is just the interface, we
need a good implementation as the default

Fixes LP #1040236

Change-Id: If6e65cb1c7802b1ba0c1e64d4c06185cabf9eeca

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