OAK-812 QueryEngine support for multiple indices (tests)
 - found a small bug in the property index editor
 - added a protected flag to prevent the query engine to fallback to node traversal during the tests

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1479909 13f79535-47bb-0310-9956-ffa450edef68