QPID-5800: [Java Broker] Add DurableConfigurationStore#onDelete method to allow an implementation to
delete the files/tables/databases underlying the store.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1600932 13f79535-47bb-0310-9956-ffa450edef68
QPID-5802: [Java Broker] Temporarily remove the slow message store and quota message store
test implementations and the tests that rely on them.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1600933 13f79535-47bb-0310-9956-ffa450edef68