Fix NPE in TestSlowQueryReport test

The TestSlowQueryReport L107 calls "new SlowQueryReportJmx().getObjectName(..)",
and thus properties field in new SlowQueryReportJmx is never set
and accessing it caused NPE in getObjectName(..).

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1460313 13f79535-47bb-0310-9956-ffa450edef68