message: Fix two minor input generator bugs
  Fix - do not attempt to open the default file name
  Also disable the "Submit calculation" if Molequeue is not running
diff: @@ -449,15 +449,6 @@ void InputGeneratorWidget::saveSingleFile(const QString& fileName)
  settings.setValue(settingsKey("outputDirectory"),
  QFileInfo(filePath).absoluteDir().absolutePath());
  - QFileInfo info(filePath);
  -
  - // Don't check for overwrite: the file save dialog takes care of this.
  - // Attempt to open the file for writing
  - if (!QFile(fileName).open(QFile::WriteOnly)) {
  - showError(tr("%1: File exists and is not writable.").arg(fileName));
  - return;
  - }
  -
  QTextEdit* edit = m_textEdits.value(fileName, nullptr);
  if (!edit) {
  showError(tr("Internal error: could not find text widget for filename '%1'")
  @@ -629,10 +620,17 @@ void InputGeneratorWidget::connectButtons()
  SLOT(updatePreviewText()));
  connect(m_ui->defaultsButton, SIGNAL(clicked()), SLOT(defaultsClicked()));
  connect(m_ui->generateButton, SIGNAL(clicked()), SLOT(generateClicked()));
  - connect(m_ui->computeButton, SIGNAL(clicked()), SLOT(computeClicked()));
  connect(m_ui->closeButton, SIGNAL(clicked()), SIGNAL(closeClicked()));
  connect(m_ui->warningTextButton, SIGNAL(clicked()),
  SLOT(toggleWarningText()));
  +
  + // disable the compute button if Molequeue is not running
  + MoleQueueManager& mqManager = MoleQueueManager::instance();
  + if (!mqManager.connectIfNeeded()) {
  + m_ui->computeButton->setEnabled(false);
  + } else {
  + connect(m_ui->computeButton, SIGNAL(clicked()), SLOT(computeClicked()));
  + }
  }
  void InputGeneratorWidget::updateOptions()
  