SLING-2945 : using different repository paths to avoid potential concurrency problem with repository deletion between testruns

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1499970 13f79535-47bb-0310-9956-ffa450edef68
SLING-2945 : avoid deadlock in HeartbeatHandler : not using both this and lock as sync objects, that was not the intention, one sync object is enough and that's the lock object.

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1499977 13f79535-47bb-0310-9956-ffa450edef68
SLING-2945 : moving setting of discoveryService also under synchronized protection

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1499980 13f79535-47bb-0310-9956-ffa450edef68
travis experiment
run, travis, run