OAK-2049 ArrayIndexOutOfBoundsException in Segment.getRefId()
 - added protection for the ArrayIndexOutOfBoundsException, added segmentid to the error logs

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1620898 13f79535-47bb-0310-9956-ffa450edef68