Change in K4 ticket cache format

[Alejandro R. Sedeno]

So, I've got a version of the patch to test, it's at:

http://web.mit.edu/asedeno/www/krb4-tkt-fix.diff
/afs/athena.mit.edu/user/a/s/asedeno/www/krb4-tkt-fix.diff

For endian checking, rather than duplicating code in
lib/crypto/aes/aesopt.h, I just #included the file in
lib/krb4/tf_util.c.

I have not been able to fully test the big endian half of the fix, as
I've only had sparc to test on, and that's LLP64, so sizeof(long) is
still 4 bytes. What testing I did there seemed to work fine.

If someone else has a big endian system where sizeof(long) == 8 on which
to test 32/64-bit interoperability, I'd appreciate any feedback.

My little endian testing was done on x86_64, and there things seem fine.

-Alejandro