[krbdev.mit.edu #6647] Memory leak in kdc

[Greg Hudson via RT]

Of course, reply (the non enc-part) is also treated as a container full
of aliases, except for reply.padata, which is treated as owned memory
and initialized/cleaned up.  So, fragile as that is, perhaps it's more
consistent with the current design (such as it is) of the function to
treat reply_encpart.enc_padata as owned memory similarly.

Also a less invasive fix for 1.8.