Fix leak in KERB_AP_OPTIONS_CBT server support

In check_cbt(), use a local variable to hold the retrieved authdata
list, and free it before returning.

https://github.com/krb5/krb5/commit/bf2ddff13c178e0c291f8fb382b040080d159e4f
Author: Greg Hudson <ghudson@mit.edu>
Commit: bf2ddff13c178e0c291f8fb382b040080d159e4f
Branch: master
 src/lib/gssapi/krb5/accept_sec_context.c |   23 +++++++++++++----------
 1 files changed, 13 insertions(+), 10 deletions(-)