Enable update and reset button only if dirty
    
    https://fedorahosted.org/freeipa/ticket/1697
    
    Original problem:
    WEBUI: Update automount location refer to unknown command
    Update name of the automount location (Policy -> Automount ->
    custom_location -> Settings -> Update) in the WEBUI refer to an unknown command.
    
    Solution:
    Tracking dirty state in field -> section -> details facet.
    'Reset' and 'Updates' in details facet are enabled only if facet is dirty.
    
    Removes the problem above and 'no modification to be performed' annoyance.