[db-wg] Suggestion further validity-checking

Edward Shryane via db-wg wrote on 28/05/2019 12:12:
> Unfortunately, no cleanup was done when this rule was implemented,
> but in recent times we try to do this. I will also contact the
> maintainers of these route objects and ask them to fix the holes
> attribute(s).
I wonder if this key should be formally deprecated.  It's used for 643 
out of 302354 route: objects and 40 out of 28803 route6: objects, i.e. 
~0.2% and 0.1% respectively. The complexity associated with handling it 
is substantial and most tools simply ignore it.

Nick