Improve block database load error reporting

src/qt/bitcoingui.h

@@ -126,8 +126,9 @@ public slots:
        @param[in] message   the displayed text
        @param[in] style     modality and style definitions (icon and used buttons - buttons only for message boxes)
                             @see CClientUIInterface::MessageBoxFlags
+       @param[in] ret       pointer to a bool that will be modified to whether Ok was clicked (modal only)
     */
-    void message(const QString &title, const QString &message, unsigned int style);
+    void message(const QString &title, const QString &message, unsigned int style, bool *ret = NULL);
     /** Asks the user whether to pay the transaction fee or to cancel the transaction.
        It is currently not possible to pass a return value to another thread through
        BlockingQueuedConnection, so an indirected pointer is used.