fixed wording of an error message

apps/launcher/maindialog.cpp

@@ -753,11 +753,11 @@ void Launcher::MainDialog::play()
 
     if(!mGameSettings.hasMaster()) {
             QMessageBox msgBox;
-            msgBox.setWindowTitle(tr("No master file selected"));
+            msgBox.setWindowTitle(tr("No game file selected"));
             msgBox.setIcon(QMessageBox::Warning);
             msgBox.setStandardButtons(QMessageBox::Ok);
-            msgBox.setText(tr("<br><b>You do not have any master files selected.</b><br><br> \
-                              OpenMW will not start without a master file selected.<br>"));
+            msgBox.setText(tr("<br><b>You do not have no game file selected.</b><br><br> \
+                              OpenMW will not start without a game file selected.<br>"));
             msgBox.exec();
             return;
     }