Move the decoration window back to the padding position after each resize

Behavior seems to have changed in Qt 5. Without doing the move the deco
has a wrong position and all mouse interaction is broken after the first
resize.

And with this change Oxygen windeco in compositing is fully functional!

client.cpp

@@ -647,6 +647,7 @@ void Client::resizeDecoration(const QSize& s)
     } else {
         triggerDecorationRepaint();
     }
+    Xcb::moveWindow(decoration->widget()->winId(), -padding_left, -padding_top);
     updateInputWindow();
 }