avoid creation of an ArrayList while we always send the LDIF string of a single entry


git-svn-id: https://svn.apache.org/repos/asf/directory/apacheds/trunk@1601718 13f79535-47bb-0310-9956-ffa450edef68
improved the way a BTree is built by clearing off leaves from memory after linking with a node


git-svn-id: https://svn.apache.org/repos/asf/directory/apacheds/trunk@1601722 13f79535-47bb-0310-9956-ffa450edef68