zebra: Allow zebra to delete self originated routes

zebra: Allow zebra to delete self originated routes

With the change to make zebra pass routes to the kernel
with the 'correct' proto name, it caused zebra to
not properly recognize them on startup again
the next time such that the route would not
be deleted.

Modify rt_netlink.c to notice that we have a
self originated route and to properly mark
the type of route it was.

Modify rib_table_sweep to mark the nexthops
as active so that when we go to delete the
self originated routes it would properly
delete from the kernel.

Fixes: #1061
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>