krb5 commit [krb5-1.11]: Use an empty challenge for the password question

[Tom Yu]

https://github.com/krb5/krb5/commit/e24793e6b55d41dab55bbb53d6375177195023a2
commit e24793e6b55d41dab55bbb53d6375177195023a2
Author: Greg Hudson <ghudson at mit.edu>
Date:   Thu Dec 13 14:53:58 2012 -0500

    Use an empty challenge for the password question
    
    If a question's challenge is NULL, it is unnecessarily difficult for a
    responder callback to detect whether it was asked.  So it's better to
    use an empty challenge when there is no challenge data to communicate.
    Do this for the "password" question.
    
    (cherry picked from commit 70f2d9a093c71624269b2317c62ad0993126bc40)
    
    ticket: 7499
    version_fixed: 1.11
    status: resolved

 src/lib/krb5/krb/gic_pwd.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/lib/krb5/krb/gic_pwd.c b/src/lib/krb5/krb/gic_pwd.c
index 8ffa342..30da8c9 100644
--- a/src/lib/krb5/krb/gic_pwd.c
+++ b/src/lib/krb5/krb/gic_pwd.c
@@ -36,7 +36,7 @@ krb5_get_as_key_password(krb5_context context,
 
         return k5_response_items_ask_question(ritems,
                                               KRB5_RESPONDER_QUESTION_PASSWORD,
-                                              NULL );
+                                              "");
     }
 
     /* If there's already a key of the correct etype, we're done.