WebUI: services without canonical name are shown correctly
    
    There is a change introduced in 4.4 that new services have canonical name. The old ones
    didn't have it, therefore these services were not correctly displayed in WebUI.
    
    This patch adds support for this type of services. Service name is taken from
    'krbprincipalname' attribute in case that 'krbcanonicalname' attribute is not present
    in server response.
    
    https://fedorahosted.org/freeipa/ticket/6397
    
    Reviewed-By: Petr Vobornik <pvoborni@redhat.com>