Fix function() argument 1 must be code, not str

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>
Fix AttributeError: 'ServersClientXML' object has no attribute 'delete_server_sync'

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>
Fix  tearDownClass() takes exactly 1 argument (0 given)

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>