Enhancement request - clear cache on "HTML response must have exactly one HEAD..." #210

We're encountering an issue where bad data is getting added to the cache via 
HttpCache.get(). We don't know what exactly the bad data is or how it ended up 
there, but we get this exception:

org.openid4java.discovery.yadis.YadisException: 0x70b: HTML response must have 
exactly one HEAD element, found 0

Once the bad data is in the cache, it seems to be getting returned for all 
subsequent requests and the exception is thrown every time (this may be a bug 
but we're not sure). We would like to submit an enhancement request where the 
cache is cleared when that exception is thrown. This would cause bad data to be 
purged when it becomes problematic rather than causing an outage for all 
subsequent requests.

This was discovered in version 0.9.5.