On 8058290: JAAS Krb5LoginModule has suspect ticket-renewal logic, relies on clockskew grace

[Weijun Wang]

Hi All

This is about the bug

    https://bugs.openjdk.java.net/browse/JDK-8058290

I'm now thinking that with renewTGT=true we should always renew the 
ticket no matter if it's new or old. This means the TGT will be always 
the latest inside the subject.

How is your opinion? The source fix will be easy but I'd like to get 
some feedback before writing regression tests for it.

Thanks
Max