[krbdev.mit.edu #3334] libkrb5 treats all KDC errors as terminal

[lukeh@padl.com via RT]

If a KDC returns KDC_ERR_SVC_UNAVAILABLE, it appears that that the
client library will not failover to the next KDC. All error codes,
except for KDC_ERR_RESPONSE_TOO_BIG, are treated as terminal.

This won't be completely trivial to fix but I will look into it as
it causing a real problem at a customer.

-- Luke

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