OAK-2236 - Support queries with only order by specified

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1634896 13f79535-47bb-0310-9956-ffa450edef68
OAK-2237: NodeStoreKernel.getNodes throws when passing filter=""

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1634898 13f79535-47bb-0310-9956-ffa450edef68