lib-smtp: server: Fix overwriting a previously submitted reply.

The submitted flag was not reset, nor was the replies_submitted counter
decreased. This caused assertion failures.

src/lib-smtp/smtp-server-reply.c

@@ -50,7 +50,7 @@ smtp_server_reply_debug(struct smtp_server_reply *reply,
  * Reply
  */
 
-static void smtp_server_reply_clear(struct smtp_server_reply *reply)
+static void smtp_server_reply_destroy(struct smtp_server_reply *reply)
 {
 	if (reply->command == NULL)
 		return;
@@ -62,6 +62,16 @@ static void smtp_server_reply_clear(struct smtp_server_reply *reply)
 	str_free(&reply->content->text);
 }
 
+static void smtp_server_reply_clear(struct smtp_server_reply *reply)
+{
+	smtp_server_reply_destroy(reply);
+	if (reply->submitted) {
+		i_assert(reply->command->replies_submitted > 0);
+		reply->command->replies_submitted--;
+	}
+	reply->submitted = FALSE;
+}
+
 static struct smtp_server_reply *
 smtp_server_reply_alloc(struct smtp_server_command *cmd, unsigned int index)
 {
@@ -160,7 +170,7 @@ void smtp_server_reply_free(struct smtp_server_command *cmd)
 	for (i = 0; i < cmd->replies_expected; i++) {
 		struct smtp_server_reply *reply =
 			array_idx_modifiable(&cmd->replies, i);
-		smtp_server_reply_clear(reply);
+		smtp_server_reply_destroy(reply);
 	}
 }