Revert "bump to 2.6.4 for maven"

This reverts commit 5d236e31b175790204856afffb7b23ad1a19a078.
Revert "update to 2.6.4 (latest stable version)"

This reverts commit cfd78d4ed9b2810de02eb9c84aab274f2a33cba5.
Revert "update jackrabbit webdav lib to version 2.6.3"

This reverts commit 44acb753ef34fa40f31d74818341955f2816ec15.