* g10/call-keyboxd.c (gpg_keyboxd_deinit_session_data): Release
the assuan connection before kbx_client_data_release.
(open_context): Enable use of the data pipe.
* sm/keydb.c (gpgsm_keydb_deinit_session_data): Release the
assuan connection before kbx_client_data_release.
(open_context): Enable use of the data pipe.
* kbx/kbx-client-util.c (struct kbx_client_data_s): Add THD field.
(prepare_data_pipe): Close the pipe output end as it's been sent
already.  Remember the KCD->THD, so that it can be joined later.
(datastream_thread): Finish when reading no data from the pipe.
(kbx_client_data_release): Join the thread.  Then, we can safely
call es_fclose on the FP.