@Override
    public ApplicationFile createDirectory() {
        Path zkPath = getZKPath(path);
        if (isDirectory()) return this;
        if (exists()) {
            throw new IllegalArgumentException("Unable to create directory, file exists: " + path);
        }
        zkApp.create(zkPath);
        writeMetaFile(ContentStatusNew);
        return this;
    }
@author Ulf Lilleengen
@author Vegard Havdal
configserver/src/main/java/com/yahoo/vespa/config/server/zookeeper/ZKApplicationFile.java