[krbdev.mit.edu #1193] Implement new key storage architecture

[Sam Hartman via RT]

During the 1.2.3 crypto transition we added code to coerce the enctype
to be what was expected by calling routines and attached the following
    /*
     * Coerce the enctype of the output keyblock in case we got an
     * inexact match on the enctype; this behavior will go away when
     * the key storage architecture gets redesigned for 1.3.
     */
legend.



Do we still want to do this for 1.3?
Presume not, but I'm opening this ticket for discussion.