[krbdev.mit.edu #9181] verify_mic_v3 broken in 1.22

[Francis Dupont via RT]

<URL: https://krbdev.mit.edu/rt/Ticket/Display.html?id=9181 >

Greg Hudson via RT writes:
> I've attached a fix, which I am fairly confident about.  (The actual commit
> will also add tests.)

=> tested it with success: it fixes the unit test with a bad GSS TSIG
(it flips a bit) without visible unexpected side effect.

Thanks

Francis Dupont <fdupont at isc.org>