FIX for webdav.mediencenter.t-online.de 
FIX for webdav.mediencenter.t-online.de 

https://webdav.mediencenter.t-online.de returns invalid response code.

e.g.
{"reqId":"f9a1c394b98108e4e5ca62bf47829c64","remoteAddr":"81.189.45.224","app":"PHP","message":"Undefined offset: 2 at \/var\/www\/owncloud\/3rdparty\/sabre\/dav\/lib\/Sabre\/DAV\/Client.php#569","level":3,"time":"2015-03-25T18:25:48+00:00","method":"GET","url":"\/index.php\/apps\/files\/ajax\/getstoragestats.php?dir=External%2FT-Cloud%2FTests"}

e.g.
{"reqId":"3407d66672b3cef206b0af883e49bff4","remoteAddr":"46.74.125.245","app":"PHP","message":"Undefined index: {DAV:}getlastmodified at \/var\/www\/owncloud\/lib\/private\/files\/storage\/dav.php#563","level":3,"time":"2015-03-25T16:33:21+00:00"}
cernbox/core,endsguy/server,IljaN/core,sharidas/core,michaelletzgus/nextcloud-server,xx621998xx/server,owncloud/core,xx621998xx/server,lrytz/core,nextcloud/server,jbicha/server,owncloud/core,Ardinis/server,pmattern/server,whitekiba/server,jbicha/server,pixelipo/server,nextcloud/server,whitekiba/server,pollopolea/core,IljaN/core,cernbox/core,michaelletzgus/nextcloud-server,andreas-p/nextcloud-server,pixelipo/server,endsguy/server,pmattern/server,bluelml/core,lrytz/core,pollopolea/core,sharidas/core,whitekiba/server,lrytz/core,endsguy/server,Ardinis/server,whitekiba/server,bluelml/core,cernbox/core,Ardinis/server,michaelletzgus/nextcloud-server,whitekiba/server,bluelml/core,pmattern/server,lrytz/core,owncloud/core,phil-davis/core,pixelipo/server,endsguy/server,lrytz/core,owncloud/core,IljaN/core,sharidas/core,cernbox/core,IljaN/core,andreas-p/nextcloud-server,bluelml/core,sharidas/core,jbicha/server,andreas-p/nextcloud-server,michaelletzgus/nextcloud-server,pixelipo/server,pollopolea/core,pollopolea/core,Ardinis/server,jbicha/server,Ardinis/server,andreas-p/nextcloud-server,jbicha/server,xx621998xx/server,andreas-p/nextcloud-server,pmattern/server,bluelml/core,pixelipo/server,endsguy/server,nextcloud/server,pollopolea/core,xx621998xx/server,cernbox/core,IljaN/core,sharidas/core,pmattern/server,xx621998xx/server,nextcloud/server,owncloud/core