Improve error handling when restoring from seedphrase

We now catch exceptions in litelib_initialize_new_from_phrase and no longer save an empty/invalid wallet
if there were errors.

src/mainwindow.cpp

@@ -209,16 +209,27 @@ MainWindow::MainWindow(QWidget *parent) :
     config->server = Settings::getInstance()->getSettings().server;
     // 3. Attempt to restore wallet with the seed phrase
     {
-        char* resp = litelib_initialize_new_from_phrase(config->dangerous, config->server.toStdString().c_str(),
-                seed.toStdString().c_str(), birthday, number);
-        QString reply = litelib_process_response(resp);
-
-        if (reply.toUpper().trimmed() != "OK") {
-            QMessageBox::warning(this, tr("Failed to restore wallet"), 
+        QString reply = "";
+        try {
+            char* resp = litelib_initialize_new_from_phrase(config->dangerous, config->server.toStdString().c_str(),
+                    seed.toStdString().c_str(), birthday, number);
+            reply = litelib_process_response(resp);
+
+            if (reply.toUpper().trimmed() != "OK") {
+                QMessageBox::warning(this, tr("Failed to restore wallet"),
+                    tr("Couldn't restore the wallet") + "\n" + reply,
+                    QMessageBox::Ok);
+                return false;
+            }
+        } catch (const std::exception& e)  {
+            //TODO: try another server with getRandomServer()
+            qDebug() << __func__ << ": caught an exception! Bailing out: " << e.what();
+            QMessageBox::warning(this, tr("Failed to restore wallet"),
                 tr("Couldn't restore the wallet") + "\n" + reply,
                 QMessageBox::Ok);
-           
-        } 
+            return false;
+        }
+
     }
 
     // 4. Finally attempt to save the wallet