Improve automount indirect map error message
    
    When user does not pass a name of parent map in
    automountmap-add-indirect command, auto.master is used as
    a default. However, when auto.master does not exist in a given
    location, we raise NotFound error with a name of a location instead
    of a name of the missing automount map.
    
    https://fedorahosted.org/freeipa/ticket/2387