minor improvement: remove unused method

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1541571 13f79535-47bb-0310-9956-ffa450edef68
OAK-685 Enforce referential integrity for referenceable nodes
 - rolling back better multiple valued properties support, bad change

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1541572 13f79535-47bb-0310-9956-ffa450edef68