RFR: 8274205: Handle KDC_ERR_SVC_UNAVAILABLE error code from KDC [v2]

[Weijun Wang]

On Fri, 24 Sep 2021 05:33:46 GMT, Alexey Bakhtin <abakhtin at openjdk.org> wrote:

>> The code change handles KDC_ERR_SVC_UNAVAILABLE error code (29) received from KDC and resends the initial request to the next KDC in the list. It aligns error code handling with the MIT Kerberos implementation.
>> sun/security/krb5 tests passed
>
> Alexey Bakhtin has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Added Unavailable test

Marked as reviewed by weijun (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/5658