Open item: kerberos warning message

Looking at the open item about the new error message shown when Kerberos
is compiled in, and not used:
assword:
FATAL: password authentication failed for user "mha"
psql: pg_krb5_init: krb5_cc_get_principal: No credentials cache found
FATAL: password authentication failed for user "mha"

The reason this is happening is that we are initializing Kerberos even
if we're not going to use it. The reason for doing *this*, is that if
kerberos is compiled in, we use it to find out if we should try a
different username than the one logged in to the local system - we look
at the kerberos login.

We don't do this for any other login, including kerberos over GSSAPI.
AFAIK, we've heard no complaints.

I see two ways to fix this, and have attached two patches:

1) Remove the support for getting this username. AFAIK, it's not even
documented. [krberror_remove.patch]

2) Suppress the error message when called from this location. If
Kerberos is actually used, we'll get the error message again later and
show it then. [krberror_suppress.patch]

Thoughts?

//Magnus