wolfsshd: remove the temp config dir on exit

The exit teardown stops the shared daemon before sweeping the registry.
stop_wolfsshd is what removes the per-daemon temp directory, which
holds the rewritten config and root-owned copies of the trust anchors,
and it is idempotent, so a run that stopped already is unaffected.

- a run that exits early, on a daemon that will not start or on a
  failed test, reaches no stop of its own and left the directory in
  /tmp with a copy of the host key in it

apps/wolfsshd/test/run_all_sshd_tests.sh

@@ -142,6 +142,11 @@ export WOLFSSHD_TEST_PIDFILE
 # script's exit status, which would turn a passing run red.
 run_teardown() {
     if [ "$USING_LOCAL_HOST" == 1 ]; then
+        # Before the sweep, and idempotent: this is what removes $SSHD_KEYDIR,
+        # the temp dir holding the rewritten config and the root-owned copies
+        # of the trust anchors. The early exits -- a daemon that will not
+        # start, a failed test -- never reach a stop of their own.
+        stop_wolfsshd || true
         stop_all_wolfsshd || true
     fi
     rm -f "$WOLFSSHD_TEST_PIDFILE" || true