Delete Kafka topics in unstack phase
Delete Kafka topics in unstack phase

unstack.sh stack.sh sequence fails because of Kafka topics not being
deleted in unstack phase.

Change-Id: I0a5e0b029b5cb2aa5bc56131e62fa6d9cfa34be9

openstack/monasca-log-api,stackforge/monasca-log-api,stackforge/monasca-log-api,openstack/monasca-log-api,openstack/monasca-log-api,stackforge/monasca-log-api