Bug#974531: krb5: Please include upstream fix "Unregister thread key in SPNEGO finalization"

[Sam Hartman]

I don't plan to ever put 1.17.2 into unstable; I plan to ask to move
1.18.2 into unstable shortly.
LTS is beyond my horizon of caring.
I won't stand in your way, and if you never became a DD, I'll be happy
to review and sponsor anything you need, but that's not where my energy
goes.