intermediate chains that it encounters on the wire and use those to try
to validate chains that might be missing intermediate certificates.
This vastly improves the number of certificates that Bro can validate.
The only drawback is that now validation behavior is not entirely
predictable anymore - the certificate of a server can fail to validate
when Bro just started up (due to the intermediate missing), and succeed
later, when the intermediate can be found in the cache.
Has been tested on big-ish clusters and should not introduce any
performance problems.
