Destroy fixture database after each gabbi TestSuite
Destroy fixture database after each gabbi TestSuite

For the sake of cleanliness and disk space management.

Change-Id: I7e5656333256c14f2c13b960be4450bfa4558ed7

chungg/aodh,maestro-hybrid-cloud/ceilometer,idegtiarov/ceilometer,r-mibu/ceilometer,redhat-openstack/ceilometer,ityaptin/ceilometer,cernops/ceilometer,openstack/aodh,chungg/aodh,redhat-openstack/ceilometer,eayunstack/ceilometer,cernops/ceilometer,fabian4/ceilometer,openstack/ceilometer,fabian4/ceilometer,idegtiarov/ceilometer,eayunstack/ceilometer,openstack/ceilometer,isyippee/ceilometer,ityaptin/ceilometer,maestro-hybrid-cloud/ceilometer,sileht/aodh,r-mibu/ceilometer,mathslinux/ceilometer,pczerkas/aodh,pczerkas/aodh,pkilambi/ceilometer,sileht/aodh,isyippee/ceilometer,mathslinux/ceilometer,openstack/aodh,pkilambi/ceilometer