Proposal: drop support for pa-sam-challenge and pa-sam-response from KDC and client

[Ken Hornstein]

>I'd really like to wrip it out.  I don't think the code is particularly
>supportable; reading it has made me concerned about the potential for
>memory leaks and in some cases security issues.

Add another vote from me for ripping out the old SAM support; as you have
noted, it's got plenty of issues.

--Ken