message: disable spinbox if no autofetch
diff: @@ -158,6 +158,7 @@ public:
  git::Config app = mRepo.appConfig();
  mFetch->setChecked(app.value<bool>("autofetch.enable", fetch));
  mFetchMinutes->setValue(app.value<int>("autofetch.minutes", minutes));
  + mFetchMinutes->setEnabled(mFetch->isChecked());
  mPushCommit->setChecked(app.value<bool>("autopush.enable", push));
  mPullUpdate->setChecked(app.value<bool>("autoupdate.enable", update));
  mAutoPrune->setChecked(app.value<bool>("autoprune.enable", prune));
  