cleaning up unit test DataSource bootstrap

Specifically in a CI environment, in-memory DBs can be bootstrapped without connection.properties

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/trunk@1542759 13f79535-47bb-0310-9956-ffa450edef68
adding hsql to the test scope

otheriwse hsqldb profile may not be activated if say 'assembly' is active
and the tests will fail

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/trunk@1542764 13f79535-47bb-0310-9956-ffa450edef68