OAK-1995 Improved SegmentNodeStore documentation (actually: remove unused class)

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1614816 13f79535-47bb-0310-9956-ffa450edef68
OAK-1995 Improved SegmentNodeStore documentation

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1614817 13f79535-47bb-0310-9956-ffa450edef68