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
```

/**
         * Mask of all available icons in CClientUIInterface::MessageBoxFlags
         * This needs to be updated, when icons are changed there!
         */
        ICON_MASK = (ICON_INFORMATION | ICON_WARNING | ICON_ERROR),
        
        BTN_OK      = 0x00000400U, 
        BTN_YES     = 0x00004000U, 
        BTN_NO      = 0x00010000U, 
        BTN_ABORT   = 0x00040000U, 
        BTN_RETRY   = 0x00080000U, 
        BTN_IGNORE  = 0x00100000U, 
        BTN_CLOSE   = 0x00200000U, 
        BTN_CANCEL  = 0x00400000U, 
        BTN_DISCARD = 0x00800000U, 
        BTN_HELP    = 0x01000000U, 
        BTN_APPLY   = 0x02000000U, 
        BTN_RESET   = 0x04000000U, 
        /**
         * Mask of all available buttons in CClientUIInterface::MessageBoxFlags
         * This needs to be updated, when buttons are changed there!
         */
        BTN_MASK = (BTN_OK | BTN_YES | BTN_NO | BTN_ABORT | BTN_RETRY | BTN_IGNORE |
                    BTN_CLOSE | BTN_CANCEL | BTN_DISCARD | BTN_HELP | BTN_APPLY | BTN_RESET),
        
        MODAL               = 0x10000000U,
        
        SECURE              = 0x40000000U,
        
        MSG_INFORMATION = ICON_INFORMATION,