ipatests: add too-restritive mask tests
    
    If the mask used during the installation is "too restrictive", ie.0027,
    installing FreeIPA results in a broken server or replica.
    Add two tests that expect an error message at install time to catch
    too restrictive masks.
    
    Related to: https://pagure.io/freeipa/issue/7193
    Signed-off-by: François Cami <fcami@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>