when authenticating against pam_krb5 before pam_unix the user can not login, 
sshd logs the error "input_userauth_info_response_pam: no authentication 
context".

i don't know why this is failing, this patch fixes the problem by removing the 
check for an authentication context.

users can now login with the pam.conf entry:

sshd auth sufficient /usr/lib/security/$ISA/pam_krb5.so.1
sshd auth required /usr/lib/security/$ISA/pam_unix.so.1 try_first_pass


*** auth2-pam.c-        Tue Feb 26 15:30:14 2002
--- auth2-pam.c Tue Feb 26 15:31:26 2002
***************
*** 134,141 ****
--- 134,143 ----
       unsigned int nresp = 0, rlen = 0, i = 0;
       char *resp;

+ /*
       if (authctxt == NULL)
               fatal("input_userauth_info_response_pam: no authentication 
context");
+ */

       nresp = packet_get_int();       /* Number of responses. */
       debug("got %d responses", nresp);