Ensure default DB connection strings use unique defaults
Ensure default DB connection strings use unique defaults

PowerDNS and Designate had the same default DB connection value, this
has now been corrected.

Change-Id: I69bc74df0bd6635c1166f3fd142884c479f0144c
Closes-Bug: 1277451

tonyli71/designate,cneill/designate,ionrock/designate,cneill/designate-testing,kiall/designate-py3,melodous/designate,cneill/designate-testing,ionrock/designate,muraliselva10/designate,kiall/designate-py3,openstack/designate,cneill/designate,grahamhayes/designate,grahamhayes/designate,cneill/designate,openstack/designate,kiall/designate-py3,melodous/designate,ramsateesh/designate,openstack/designate,kiall/designate-py3,richm/designate,NeCTAR-RC/designate,cneill/designate-testing,muraliselva10/designate,grahamhayes/designate,cneill/designate,cneill/designate,melodous/designate,ionrock/designate,tonyli71/designate,muraliselva10/designate,NeCTAR-RC/designate,richm/designate,kiall/designate-py3,tonyli71/designate,ramsateesh/designate,ramsateesh/designate,melodous/designate