Remove slot for no-longer existing signal in Slideback

Leftover from tabbing rewrite.

effects/slideback/slideback.cpp

@@ -37,7 +37,6 @@ SlideBackEffect::SlideBackEffect()
     connect(effects, SIGNAL(windowActivated(KWin::EffectWindow*)), this, SLOT(slotWindowActivated(KWin::EffectWindow*)));
     connect(effects, SIGNAL(windowDeleted(KWin::EffectWindow*)), this, SLOT(slotWindowDeleted(KWin::EffectWindow*)));
     connect(effects, SIGNAL(windowUnminimized(KWin::EffectWindow*)), this, SLOT(slotWindowUnminimized(KWin::EffectWindow*)));
-    connect(effects, SIGNAL(clientGroupItemSwitched(KWin::EffectWindow*,KWin::EffectWindow*)), this, SLOT(slotClientGroupItemSwitched(KWin::EffectWindow*,KWin::EffectWindow*)));
     connect(effects, SIGNAL(tabBoxClosed()), this, SLOT(slotTabBoxClosed()));
 }
 
@@ -69,16 +68,6 @@ void SlideBackEffect::slotWindowActivated(EffectWindow* w)
         return;
     }
 
-    if (clientItemShown == w) {
-        clientItemShown = NULL;
-        updateStackingOrder();
-        return;
-    }
-    if (clientItemHidden == w) {
-        clientItemHidden = NULL;
-        updateStackingOrder();
-        return;
-    }
     // Determine all windows on top of the activated one
     bool currentFound = false;
     foreach (EffectWindow * tmp, oldStackingOrder) {
@@ -311,12 +300,6 @@ void SlideBackEffect::slotWindowUnminimized(EffectWindow* w)
     }
 }
 
-void SlideBackEffect::slotClientGroupItemSwitched(EffectWindow* from, EffectWindow* to)
-{
-    clientItemShown = to;
-    clientItemHidden = from;
-}
-
 void SlideBackEffect::slotTabBoxClosed()
 {
     disabled = true;

effects/slideback/slideback.h

@@ -47,7 +47,6 @@ public Q_SLOTS:
     void slotWindowActivated(KWin::EffectWindow *w);
     void slotWindowDeleted(KWin::EffectWindow *w);
     void slotWindowUnminimized(KWin::EffectWindow *w);
-    void slotClientGroupItemSwitched(KWin::EffectWindow* from, KWin::EffectWindow* to);
     void slotTabBoxClosed();
 
 private:
@@ -58,8 +57,6 @@ private:
     EffectWindowList coveringWindows;
     EffectWindowList elevatedList;
     EffectWindow* unminimizedWindow;
-    EffectWindow* clientItemShown;
-    EffectWindow* clientItemHidden;
     QHash<EffectWindow *, QRect> destinationList;
     bool disabled;
     QList <QRegion> clippedRegions;