Further Webdav copy/move issues with litmus

[PVince81]

docker run -e LITMUS_URL="http://172.17.0.1:9140/remote.php/webdav/home/" -e LITMUS_USERNAME="einstein" -e LITMUS_PASSWORD="relativity" -e TESTS="copymove" owncloud/litmus:latest
-> running `copymove':
 0. init.................. pass
 1. begin................. pass
 2. copy_init............. pass
 3. copy_simple........... pass
 4. copy_overwrite........ pass
 5. copy_nodestcoll....... pass
 6. copy_cleanup.......... pass
 7. copy_coll............. pass
 8. copy_shallow.......... WARNING: Could not delete csrc
WARNING: Could not clean up cdest
    ...................... pass (with 2 warnings)
 9. move.................. FAIL (MOVE `/remote.php/webdav/home/litmus/move' to `/remote.php/webdav/home/litmus/movedest': 500 Internal Server Error)
10. move_coll............. FAIL (collection MOVE `/remote.php/webdav/home/litmus/mvsrc/' to `/remote.php/webdav/home/litmus/mvdest/': 500 Internal Server Error)
11. move_cleanup.......... pass
12. finish................ pass
<- summary for `copymove': of 13 tests run: 11 passed, 2 failed. 84.6%
-> 2 warnings were issued.
See debug.log for network/debug traces.

[PVince81]

PR here: cs3org/reva#729

this fixes the move operations but not the cleanup warning