[nsp] ospf default routes and bgp injection

[atticus at satanic.org]

> For all others, it doesn't matter whether "A" or "D" is "the default
> gateway" - as soon as your packets hit either, it will be BGP-routed.
>
> I'd actually have "A" *and* "D" inject a 0.0.0.0/0 default route into the
> IGP.   Otherwise the default route will be gone if "A" dies.

>From reading the initial post (using default-originate always) the only
thing you're missing to go along w/ this is a static default to Null0 on
"A" and "D", so they won't ever take the default from the IGP.