OAK-1724: Enable copying of Lucene index to local file system for read queries

Decrease the blob entry size to below the SegmentMK inline limit to ensure good performance even when using the SegmentMK with an external Data/BlobStore.

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1587430 13f79535-47bb-0310-9956-ffa450edef68