xmlrpc: adapt range plugin test
    
    A warning is added in ipa idrange-add/mod/del for
    local ranges. Adapt the test expectation.
    
    Related: https://pagure.io/freeipa/issue/9558
    Signed-off-by: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>