OAK-1434 : Cleanup dependencies of oak-core (WIP)
 - moving folder structure from src/main/java/org.apache.jackrabbit.oak.spi.blob/ to proper src/main/java/org/apache/jackrabbit/oak/spi/blob/

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1570500 13f79535-47bb-0310-9956-ffa450edef68