viewer: moved nouveau to application launch rather than viewer init

Viewer init was kind of too late since in many cases the sequence
would start caching and crash the app before the user could even read
the message. Moving to the startup makes it clearer from the beginning.

app/widget/viewer/viewerdisplay.cpp

@@ -38,10 +38,6 @@
 
 OLIVE_NAMESPACE_ENTER
 
-#ifdef Q_OS_LINUX
-bool ViewerDisplayWidget::nouveau_check_done_ = false;
-#endif
-
 ViewerDisplayWidget::ViewerDisplayWidget(QWidget *parent) :
   ManagedDisplayWidget(parent),
   signal_cursor_color_(false),
@@ -199,21 +195,6 @@ void ViewerDisplayWidget::initializeGL()
   ManagedDisplayWidget::initializeGL();
 
   connect(context(), &QOpenGLContext::aboutToBeDestroyed, this, &ViewerDisplayWidget::ContextCleanup, Qt::DirectConnection);
-
-#ifdef Q_OS_LINUX
-  if (!nouveau_check_done_) {
-    const char* vendor = reinterpret_cast<const char*>(context()->functions()->glGetString(GL_VENDOR));
-
-    if (!strcmp(vendor, "nouveau")) {
-      // Working with Qt widgets in this function segfaults, so we queue the messagebox for later
-      QMetaObject::invokeMethod(this,
-                                "ShowNouveauWarning",
-                                Qt::QueuedConnection);
-    }
-
-    nouveau_check_done_ = true;
-  }
-#endif
 }
 
 void ViewerDisplayWidget::paintGL()
@@ -305,18 +286,6 @@ rational ViewerDisplayWidget::GetGizmoTime()
   return GetAdjustedTime(GetTimeTarget(), gizmos_, time_, NodeParam::kInput);
 }
 
-#ifdef Q_OS_LINUX
-void ViewerDisplayWidget::ShowNouveauWarning()
-{
-  QMessageBox::warning(this,
-                       tr("Driver Warning"),
-                       tr("Olive has detected your system is using the Nouveau graphics driver.\n\nThis driver is "
-                          "known to have stability and performance issues with Olive. It is highly recommended "
-                          "you install the proprietary NVIDIA driver before continuing to use Olive."),
-                       QMessageBox::Ok);
-}
-#endif
-
 void ViewerDisplayWidget::ContextCleanup()
 {
   makeCurrent();