UTIL: Add a new domain state called DOM_INCONSISTENT
    
    This is a new domain state that indicates to the responder that it
    should always send a DP request because the provider is rebuilding the
    cache.
    
    Currently it will be only used by the files provider when it is updating
    the cache to make sure sssd always returns current data and updating the
    cache from files is not as racy.
    
    Reviewed-by: Pavel Březina <pbrezina@redhat.com>