JCR-3534: Efficient copying of binaries across repositories with the same data store

Change getIdentifierFromReference() to getRecordFromReference() to avoid problems with a previously valid reference pointing to a record that has already been removed.

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/trunk@1484444 13f79535-47bb-0310-9956-ffa450edef68