Final step to make logging actually work

This completes what https://github.com/couchbase/couchbase-lite-java-core/pull/281 started. While https://github.com/couchbase/couchbase-lite-java-core/pull/281 handles getting the logger object to let things below info through it turns out that in the standard Java logging system the handlers have their own separate filters. So even if the logger object is set to accept below info the handler is not. So this code extends the handler to also accept all. With this addition now the logging for the tests actually outputs all logging data.