Starting with txindex option produces a bug continually printing "y".

```
sudo apt-add-repository ppa:bitcoin/bitcoin
sudo apt-get update
bitcoind -daemon -txindex=1 -server=1 &
root@btc:~# Bitcoin server starting
: You need to rebuild the database using -reindex to change -txindex.

Do you want to rebuild the block database now?
yes
y
y
y
y
y
```

#include "noui.h"
#include "ui_interface.h"
#include "util.h"
#include <cstdio>
#include <stdint.h>
#include <string>
static bool noui_ThreadSafeMessageBox(const std::string& message, const std::string& caption, unsigned int style)