isisd: pull up invalid prefix assert()

processing invalid prefixes causes isisd to assert() or otherwise
misbehave in ip_masklen/apply_mask.  pull up the assert() to indicate
better there's broken data in isisd's LSDB.

  * isisd/isis_spf.c: assert() prefix lengths

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
1 file changed