Forward port rev 1169047: Block keyboard input during animations in desktop grid.

This works around crashers if a key is pressed directly after activating the effect.
Working around is not the perfect solution, but we already block mouse events, so it
is consistent. And unfortunately the effect has become difficult to maintain and I
fear it's like chasing one crash after the other if we allow user interaction during
the animations.
CCBUG: 244813

svn path=/trunk/KDE/kdebase/workspace/; revision=1169048

effects/desktopgrid/desktopgrid.cpp

@@ -747,6 +747,8 @@ void DesktopGridEffect::windowInputMouseEvent( Window, QEvent* e )
 
 void DesktopGridEffect::grabbedKeyboardEvent( QKeyEvent* e )
     {
+    if( timeline.value() != 1 ) // Block user input during animations
+        return;
     if( e->type() == QEvent::KeyPress )
         {
         // check for global shortcuts