1091919 - agent load rsa keys on demand.

https://bugzilla.redhat.com/show_bug.cgi?id=1091919

Basically, the release notes need to be more explicit in the **upgrade** section.  Also, the *Authenticator* needs to load the RSA keys on demand.  This ensures the plugin can be loaded even when the key exchange with the server has not yet taken place.  The message rate with the consumer is so low that the overhead of loading the keys each time is negligible.  Further complexity of caching the loaded key is unwarranted.