Sanity check: GSSAPI SPI simplifications

[Greg Hudson]

On Tue, 2010-04-27 at 06:17 -0400, ghudson at MIT.EDU wrote:
> I propose to get rid of it, and to eliminate gss_add_cred
> from struct gss_config.
[...]
> After this change is made, I propose to eliminate
> gss_inquire_cred from struct gss_config and remove the krb5
> implementation of it.

Since struct gss_config comes from the OpenSolaris mechglue, I'll amend
my plan to leave these fields in the structure but null out the
corresponding fields in the krb5 mech and other mechs we implement.