be more lenient when parsing alternate names

The current parser for alternate names bails out when it sees a alternative name format it doesn't understand, even when it can parse others. This prevents tls from validating certificates against a domain that is not the main subject when such unsupported alternate names are present. 
My patch changes the parser to ignore any fields it doesn't understand. This is certainly a crude hack, but it at least allows me to connect to the server. 

As an example, this gist (https://gist.github.com/Philonous/9452127 ) includes a certificate for jabberd.draugr.de, to which you would usually connect via the alternate name draugr.de .