ospfd: CVE-2011-3326 (uknown LSA type segfault)

ospfd: CVE-2011-3326 (uknown LSA type segfault)

This vulnerability (CERT-FI #514837) was reported by CROSS project.
They have also suggested a fix to the problem, which was found
acceptable.

Quagga ospfd does not seem to handle unknown LSA types in a Link State
Update message correctly. If LSA type is something else than one
supported
by Quagga, the default handling of unknown types leads to an error.

* ospf_flood.c
  * ospf_flood(): check return value of ospf_lsa_install()