ripd: correctly redistribute ifindex routes (BZ#664)

ripd: correctly redistribute ifindex routes (BZ#664)

ripd had a check to restrict metric 0 to only directly connected routes.
This check was implemented by checking against Connected as route type.
This is, however, incorrect -- all routes that directly use an interface
without a nexthop should be treated as directly connected and passed off
with metric 0.

ripngd does not posess such a check and was not touched.

Reported-by: Sean Fulton <sean@gcnpublishing.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>