OAK-2005 - Use separate Lucene index for performing property related queries

Fix issue with resetting of 'dirty' flag. It should be OR ed with the result such that it does not get reset to false.

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1635435 13f79535-47bb-0310-9956-ffa450edef68
OAK-2230: Execution Stats for async indexing
Remove custom executor from ExecutionStats and schedule execution updates for time series through AsyncIndexStats in Oak class.
Made access private for Execution stats and not resetting consolidated stats.

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1635436 13f79535-47bb-0310-9956-ffa450edef68