Fix leak in kadm5_hook interface

In k5_kadm5_hook_free_handles(), free each handle structure as well as
its module data.

(cherry picked from commit 40f25ae58415304006dd66ad55eeeb7505d1a816)

https://github.com/krb5/krb5/commit/176642a6bac5c6796d4b23124fdc2ed27a0358dc
Author: Greg Hudson <ghudson@mit.edu>
Committer: Tom Yu <tlyu@mit.edu>
Commit: 176642a6bac5c6796d4b23124fdc2ed27a0358dc
Branch: krb5-1.14
 src/lib/kadm5/srv/kadm5_hook.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)