GSSAPI delegation wierdness, a DOS, and channel bindings

[Sam Hartman]

Hi.  Per my comments last night I have committed your patch (along
with trivial modifications to make it build on mainline).  The hunks
dealing with allowing no channel bindings support and the DOS fix were
already committed.

I've tested the patch on a 1.2 codebase, but I don't have a good
server setup to test the mainline patch very well.  What testing I
have done (use ftpd) works fine.

I have not yet committed changes to make use encrypt for rc4 and
future crypto systems; I'll look at how to do that fairly soon.  I
have a bug open (krb5-libs/1054) on this issue.