When deleting a user using the OCS api we want to delete the users home
space. Now to completely delete a space you need to send two requests.
First to 'disable' a space and a second one to really purge it.
This commit introduces this second purge request.
Furthermore the OCS api now also deletes all spaces owned by the user
not only the home space. This is needed since some tests create project
spaces and then lookup the space by name. When doing multiple runs
though the tests will find several spaces with the same name and will
sometimes choose the wrong one which leads to test failures.

The whole test tear down should be changed to correctly clean up the
test setup.