webdav/ownCloud: do not require authentication to access status.php

Acked-by:
Target: master
Require-book: no
Require-notes: no
Merge pull request #633 from kofemann/oc2

webdav/ownCloud: do not require authentication to access status.php
Merge branch '2.8-cloud' of https://github.com/dCache/dcache into 2.8-cloud