Fix polishItems bug
Fix polishItems bug

updatePolish is not called for items which are not visible.
However if a polish is scheduled, updatePolish has to be called when the item
becomes eventually visible.

This patch makes sure, that invisible items are not removed from the itemsToPolish list.

Change-Id: I1ad929dc6de8e61edbd1c4df88ae5bc951979ff1
Reviewed-by: Ulf Hermann <e18762205ac3385fdfec64f687142c888dc97458@digia.com>
Reviewed-by: Simon Hausmann <a975102812d593b3191088e3d0aeaeb6f11dbcf5@digia.com>

mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d