Cannot invoke tr fix

This reverts commit a95eb475c7.

src/controller.cpp

@@ -1444,8 +1444,8 @@ void Controller::unlockIfEncrypted(std::function<void(void)> cb, std::function<v
         // Wallet is encrypted and locked. Ask for the password and unlock.
         QString password = QInputDialog::getText(
             main, 
-            main->tr("Wallet Password"), 
-            main->tr("Your wallet is encrypted.\nPlease enter your wallet password"), 
+            QObject::tr("Wallet Password"), 
+            QObject::tr("Your wallet is encrypted.\nPlease enter your wallet password"), 
             QLineEdit::Password
         );
 
@@ -1453,8 +1453,8 @@ void Controller::unlockIfEncrypted(std::function<void(void)> cb, std::function<v
         {
             QMessageBox::critical(
                 main, 
-                main->tr("Wallet Decryption Failed"),
-                main->tr("Please enter a valid password"),
+                QObject::tr("Wallet Decryption Failed"),
+                QObject::tr("Please enter a valid password"),
                 QMessageBox::Ok
             );
             error();
@@ -1473,7 +1473,7 @@ void Controller::unlockIfEncrypted(std::function<void(void)> cb, std::function<v
             {
                 QMessageBox::critical(
                     main, 
-                    main->tr("Wallet Decryption Failed"),
+                    QObject::tr("Wallet Decryption Failed"),
                     QString::fromStdString(reply["error"].get<json::string_t>()),
                     QMessageBox::Ok
                 );
@@ -1543,7 +1543,7 @@ void Controller::executeTransaction(Tx tx,
             error("", errStr);
         });
     }, [=]() {
-        error("", main->tr("Failed to unlock wallet"));
+        error("", QObject::tr("Failed to unlock wallet"));
     });
 }