Trace log on k5tls load failure

If sendto_kdc fails to establish an MS-KKDCP connection because the
k5tls module cannot be loaded, output a trace log before closing the
connection.  Reported by Jochen Hein.

https://github.com/krb5/krb5/commit/d43d811ea80966434910619b479212f3ed987ca4
Author: Greg Hudson <ghudson@mit.edu>
Commit: d43d811ea80966434910619b479212f3ed987ca4
Branch: master
 src/include/k5-trace.h       |    2 ++
 src/lib/krb5/os/sendto_kdc.c |    6 +++++-
 2 files changed, 7 insertions(+), 1 deletions(-)