Resolves: tdf#115106 don't assume fullscreen is impress

writer can too, so revert this part of

commit 277395b6
Author: Caolán McNamara <caolanm@redhat.com>
Date:   Tue Jun 13 18:09:08 2017 +0100

    make opengl transitions under X flicker free on enter/leave

which should restore matters to its former glory, at this point gtk3 opengl
transition support now works so it all moot to me now.

Change-Id: I78a8a774aead6482d0541575dbf10ad977ceccc0
Reviewed-on: https://gerrit.libreoffice.org/48207Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

vcl/unx/gtk/gtksalframe.cxx

@@ -2789,9 +2789,7 @@ gboolean GtkSalFrame::signalExpose( GtkWidget*, GdkEventExpose* pEvent, gpointer
 {
     GtkSalFrame* pThis = static_cast<GtkSalFrame*>(frame);
 
-    const bool bImmediate = OpenGLHelper::isVCLOpenGLEnabled() || pThis->m_bFullscreen;
-
-    struct SalPaintEvent aEvent( pEvent->area.x, pEvent->area.y, pEvent->area.width, pEvent->area.height, bImmediate );
+    struct SalPaintEvent aEvent( pEvent->area.x, pEvent->area.y, pEvent->area.width, pEvent->area.height, OpenGLHelper::isVCLOpenGLEnabled() );
 
     pThis->CallCallback( SalEvent::Paint, &aEvent );