[krbdev.mit.edu #7566] krb5-1.10.3 - Ticket lifetimes can be "negative" (this is a bad idea)

[Greg Hudson via RT]

Just as a note, the expire.exp test in lib/rpc/unit-test takes advantage 
of this behavior (it requests a TGT with a lifetime of -1 minute in order 
to exercise the GSS acceptor expiration check).  The requirements of the 
test shouldn't drive the implementation behavior, but we'll need to 
rewrite the test if we change the KDC.