De-duplicate user profile attribute values

[rrenomeron-gov]

I've discovered what I think is an issue with deserialization of the SAML2Profile class involving the authnContexts property. When it is deserialized, Jackson will populate the authenticationAttributes map in the object normally. But when it tries to populate the authnContexts property by calling its setter, it inserts a duplicate value into the authenticationAttributes map, as it tries to "merge" the multiple values.

As this happens on every read from JSON storage, the authenticationAttributes map gets really big really quickly (doubles on every serialization round trip). This causes big issues in my CAS ticket registry storage for a fairly common usage
pattern (user logs in to 5 or 6 different services on a single SSO session).

To fix, I made a small change to BasicUserProfile.mergeCollectionAttributes() which simply deduplicates multiple values from the two Collections. I'm thinking there's not a use case out there where somebody needs to have duplicate attribute values. I've done some testing in my nonproduction deployments, and it fixes the problem.

[leleuj]

Excellent! Thanks

[leleuj]

I just cut the v6.0.3 release. It will show up soon in the Maven central repository.