* kbx/keybox.h (keybox_compress_when_no_other_users): Rename from
keybox_compress, changing the arguments and the return type.
* kbx/keybox-update.c (keybox_compress_when_no_other_users): Open the
HD internally and make sure all resources are closed before unlocking.
* g10/keydb.c (keydb_add_resource): Simply call
keybox_compress_when_no_other_users which handles locking internally.
* sm/keydb.c (keydb_add_resource): Likewise.