SLING-2827 :  discovery.impl: a resource based implementation of the discovery.api . Apply another patch from Stefan Egli (activate and changing patch)

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1470555 13f79535-47bb-0310-9956-ffa450edef68
Add discovery impl to reactor

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1470557 13f79535-47bb-0310-9956-ffa450edef68