auth: Log policy decisions clearly

src/auth/auth-request.c

@@ -1026,9 +1026,22 @@ static
 void auth_request_policy_check_callback(int result, void *context)
 {
 	struct auth_policy_check_ctx *ctx = context;
+	const char *action;
 
 	ctx->request->policy_processed = TRUE;
 
+	if (result < 0)
+		action = "drop connection";
+	else if (result == 0)
+		action = "continue";
+	else
+		action = t_strdup_printf("tarpit %d second(s)", result);
+	if (result != 0)
+		auth_request_log_info(ctx->request, "policy", "Policy check action is %s",
+				      action);
+	else
+		auth_request_log_debug(ctx->request, "policy", "Policy check action is %s",
+				       action);
 	if (result == -1) {
 		/* fail it right here and now */
 		auth_request_fail(ctx->request);