lib/krb5_wrap: Remove unused smb_krb5_get_creds

lib/krb5_wrap: Remove unused smb_krb5_get_creds

Found by callcatcher

This has been unsused since

commit 61f0b247633501d6bf4103ca8345048e537c043d
Author: Günther Deschner <gd@samba.org>
Date:   Thu Nov 12 15:42:03 2009 +0100

    s3-kerberos: remove smb_krb5_get_tkt_from_creds().

    Now that cli_krb5_get_ticket() already handles S4U2SELF impersonation, remove
    smb_krb5_get_tkt_from_creds() which is not required anymore.

    Guenther

Andrew Bartlett

Autobuild-User: Andrew Bartlett <abartlet@samba.org>
Autobuild-Date: Sun Jun  3 13:04:06 CEST 2012 on sn-devel-104